Track Fundamentals
Short Description
This manual provides a description of basic track infrastructure and it components as a beginner’s guide to railway tra...
Description
TMC 202 TRACK FUNDAMENTALS Version 2.3 Issued June 2012
Owner:
Chief Engineer Track
Approved by:
Andrew Wilson Technical Specialist Wheel/Rail
Authorised by:
Malcolm Kerr Chief Engineer Track
Disclaimer This document was prepared for use on the RailCorp Network only. RailCorp makes no warranties, express or implied, that compliance with the contents of this document shall be sufficient to ensure safe systems or work or operation. It is the document user’s sole responsibility to ensure that the copy of the document it is viewing is the current version of the document as in use by RailCorp. RailCorp accepts no liability whatsoever in relation to the use of this document by any party, and RailCorp excludes any liability which arises in any manner by the use of this document. Copyright The information in this document is protected by Copyright and no part of this document may be reproduced, altered, stored or transmitted by any person without the prior consent of RailCorp.
UNCONTROLLED WHEN PRINTED
Page 1 of 184
Engineering Manual
Engineering Manual Track
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Document control Version
Date
Summary of change
1.0
October 2006
First issue as a RailCorp document. Includes content from TS 3102, RC 4800, RTS 3640, RTS 3648, CTN 04/09, CTN 05/21, CTN 05/26, CTN 06/21
2.0
April 2007
Added Dictionary of Track Terms; Added Zero toe load fastenings and rail identification picture; Added photos of hand tools; Correction of labelling of Figure 207; Inclusion of table of radius and formula; New photos of Rail Flaw Detection car
2.1
December 2008
Changes to Section C5-5 to include four foot guard rails in catchpoints; New Section C6-1.12 - In-bearers; Changes to Section C6-3.6.5 showing monobloc crossing; Chapter 8 - Changes to figure of geometry terms
2.2
December 2009
Format change only
2.3
June 2012
See Summary of changes below
Summary of changes from previous version Summary of change
Chapter
Control changes
Control Pages
Reformatted to new template – Page numbering converted to continuous numbering. Separate document control on individual chapters removed Correction of incorrect caption in Figure 20
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
All C2-3.2
Page 2 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Contents Chapter 1 C1-1 C1-2 C1-3 C1-4
Introduction ........................................................................................................................6 Purpose................................................................................................................................6 Context.................................................................................................................................6 How to read the Manual.......................................................................................................6 References...........................................................................................................................6
Chapter 2 C2-1 C2-2 C2-3 C2-4
Railway terms .....................................................................................................................8 General track terms .............................................................................................................8 General railway terms ..........................................................................................................8 Other Railway terms ..........................................................................................................13 Dictionary of track terms ....................................................................................................25
Chapter 3 C3-1 C3-2 C3-3
Track Components ..........................................................................................................38 Formation ...........................................................................................................................38 Drainage.............................................................................................................................39 Capping layer .....................................................................................................................41
Chapter 4 C4-1 C4-2 C4-3 C4-4 C4-5 C4-6 C4-7 C4-8 C4-9 C4-10 C4-11
Track..................................................................................................................................42 Ballast ................................................................................................................................42 Sleepers .............................................................................................................................43 Concrete slab track ............................................................................................................46 Sleeper plates ....................................................................................................................46 Resilient baseplates...........................................................................................................47 Sleeper fastenings .............................................................................................................48 Anchors ..............................................................................................................................55 Rail .....................................................................................................................................55 Rail Joints...........................................................................................................................58 Rail welds...........................................................................................................................60 Rail lubricators ...................................................................................................................62
Chapter 5 C5-1 C5-2 C5-3 C5-4 C5-5 C5-6 C5-7
Track layouts ....................................................................................................................64 Turnouts .............................................................................................................................64 Crossover...........................................................................................................................67 Diamond.............................................................................................................................67 Slips ...................................................................................................................................68 Catch points .......................................................................................................................69 Derailer...............................................................................................................................70 Expansion Switches...........................................................................................................71
Chapter 6 C6-1 C6-2 C6-3 C6-4 C6-5
Turnout Components ......................................................................................................72 Points .................................................................................................................................72 Closure rails .......................................................................................................................84 Crossing .............................................................................................................................84 Checkrail unit .....................................................................................................................92 Operation of points.............................................................................................................94
Chapter 7 Tools and plant.................................................................................................................97 C7-1 Manual tools.......................................................................................................................97 C7-2 Small plant ...................................................................................................................... 100
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 3 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
C7-3 C7-4 C7-5 C7-6 C7-7 C7-8 C7-9
Off track plant.................................................................................................................. 103 Resurfacing machines .................................................................................................... 104 Turnout transporter and layer ......................................................................................... 105 Ballast cleaners............................................................................................................... 106 Track Laying Machine (TLM) .......................................................................................... 107 Rerailing plant ................................................................................................................. 107 Rail grinder...................................................................................................................... 108
Chapter 8 C8-1 C8-2 C8-3 C8-4
Track Geometry............................................................................................................. 109 Simple geometry ............................................................................................................. 109 Curves............................................................................................................................. 111 Grade .............................................................................................................................. 115 Track Geometry terms .................................................................................................... 116
Chapter 9 C9-1 C9-2 C9-3 C9-4 C9-5 C9-6 C9-7 C9-8 C9-9 C9-10 C9-11
Measuring Track Geometry.......................................................................................... 119 Use of Non Metallic tapes ............................................................................................... 119 Using a level board ......................................................................................................... 119 Measuring gauge ............................................................................................................ 121 Measuring cross-level/superelevation ............................................................................ 122 Measuring alignment....................................................................................................... 123 Measuring line................................................................................................................. 124 Rail Level ........................................................................................................................ 126 Rail Top........................................................................................................................... 126 Clearance to structures................................................................................................... 127 Track centres .................................................................................................................. 128 Measuring turnouts ......................................................................................................... 128
Chapter 10 Track Inspection ........................................................................................................... 130 C10-1 Track Patrol..................................................................................................................... 130 C10-2 Mechanised Track Patrol ................................................................................................ 130 C10-3 Detailed Walking Inspection............................................................................................ 131 C10-4 Engine Inspection ........................................................................................................... 132 C10-5 Detailed Examinations .................................................................................................... 132 C10-6 Track Geometry Recording Car ...................................................................................... 132 C10-7 Rail Flaw Detection ......................................................................................................... 133 C10-8 Misalignment Prevention................................................................................................. 134 C10-9 Heat Patrol ...................................................................................................................... 134 C10-10 Out of Course Inspections .............................................................................................. 134 Chapter 11 Track Maintenance Practice......................................................................................... 135 C11-1 Geometry ........................................................................................................................ 135 C11-2 Rail .................................................................................................................................. 137 C11-3 Rail Joints........................................................................................................................ 140 C11-4 Sleepers .......................................................................................................................... 142 C11-5 Ballast ............................................................................................................................. 145 C11-6 Drainage.......................................................................................................................... 147 C11-7 Formation and earthworks .............................................................................................. 148 C11-8 Turnouts .......................................................................................................................... 149 C11-9 Clearances and obstructions .......................................................................................... 151 C11-10 Right of way .................................................................................................................... 152 C11-11 Housekeeping ................................................................................................................. 152 © Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 4 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Chapter 12 Ballast reconditioning methods .................................................................................. 154 C12-1 Manual reconditioning..................................................................................................... 154 C12-2 Ballast cleaning ............................................................................................................... 154 C12-3 Track reconditioning........................................................................................................ 155 Chapter 13 Resleepering.................................................................................................................. 157 C13-1 Manual resleepering ....................................................................................................... 157 C13-2 Mechanised resleepering................................................................................................ 157 C13-3 Track laying machine ...................................................................................................... 158 Chapter 14 Maintaining Track Geometry........................................................................................ 161 C14-1 Maintaining track alignment and line .............................................................................. 161 C14-2 Lifting and levelling ......................................................................................................... 161 C14-3 Resurfacing ..................................................................................................................... 161 C14-4 Machine types ................................................................................................................. 162 C14-5 Preliminary work ............................................................................................................. 164 C14-6 Identify any other associated work needed .................................................................... 165 Chapter 15 Rail Adjustment Fundamentals ................................................................................... 166 C15-1 Introduction ..................................................................................................................... 166 C15-2 What is a misalignment?................................................................................................. 166 C15-3 What causes a misalignment? ........................................................................................ 167 C15-4 Temperature effects in rails ............................................................................................ 167 C15-5 Control of expansion and contraction ............................................................................. 168 C15-6 Providing and maintaining lateral resistance .................................................................. 171 C15-7 Maintenance of Track Stability........................................................................................ 171 C15-8 Prevention of misalignments........................................................................................... 173 Chapter 16 Irregularities .................................................................................................................. 176 C16-1 Derailments and collisions .............................................................................................. 176 C16-2 Misalignments and pull-ins.............................................................................................. 177 C16-3 Breakaways & Broken Rails............................................................................................ 177 C16-4 Washaways..................................................................................................................... 178 C16-5 Obstructions .................................................................................................................... 180 Chapter 17 Speed Restrictions ....................................................................................................... 181 C17-1 Permanent speeds.......................................................................................................... 181 C17-2 Temporary speed restrictions ......................................................................................... 182
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 5 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Chapter 1 Introduction C1-1
Purpose This manual provides a description of basic track infrastructure and it components as a beginner’s guide to railway track. It also provides some explanation of basic maintenance and renewal techniques.
C1-2
Context This manual is part of RailCorp's engineering standards and procedures publications. More specifically, it is part of the Civil Engineering suite that comprises standards, installation and maintenance manuals and specifications.
C1-3
How to read the Manual The best way to find information in the manual is to look at the Table of Contents starting on page 3. Whilst the manual starts with very basic information and progresses to more complex concepts and it is recommended that you read the earlier chapters first, the Table of Contents is self-explanatory. Reference is made to other Manuals in which more detailed information is available.
C1-4
References
C1-4.1
Australian and International Standards Nil
C1-4.2
RailCorp Documents TMC 203 – Track Inspection TMC 211 – Track Geometry and Stability TMC 221 – Rail Installation & Repair TMC 222 – Rail Welding TMC 223 – Rail Adjustment TMC 224 – Rail Defects & Testing TMC 225 – Rail Grinding TMC 226 – Rail Defects Handbook TMC 231 – Sleepers TMC 241 – Ballast TMC 251 – Turnouts TMC 403 – Track Reconditioning Guidelines TMC 411 – Earthworks
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 6 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
TMC 421 – Track Drainage TMC 501 – Bushfire Hazard Management TMC 511 – Fencing
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 7 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Chapter 2 Railway terms This chapter provides an introductory explanation of railway terminology.
C2-1
General track terms Rail corridor The rail corridor is the area of land set aside by law for railway use. In RailCorp it is generally fenced and extends, usually, from fence to fence either side of the track. Track or Permanent Way This is the path that carries the rolling stock, or trains. It is made of rails, sleepers, and fastenings joined together and held in position by the ballast. The “four foot” This is the area between the two rails of a track. The name comes from the old measurement of the gauge (4 foot 8 ½ inches) but it has become a standard term. The “six foot” This is the area between two tracks. The name comes from the old measurement of the space. The “cess” This is the area from the edge of the ballast profile to either the edge of the embankment or the toe of the cutting.
Cess Cess “Six Foot” “Four Foot”
“Four Foot”
Figure 1 – Track terms
C2-2
General railway terms Running Line Is a line (other than a siding) that is used for the through movement of trains.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 8 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Relief lines and Crossing loops These are extra tracks in the form of loops to allow passing movements of trains.
Crossing Loop Figure 2 – Crossing Loop On double lines they are called Relief Lines, allowing faster trains to overtake slower trains. On single lines they are called Crossing Loops. Crossing loops allow faster trains to overtake slower trains and trains running in opposite directions to pass each other. Sidings Sidings are usually only connected to the running line at one end and are used to: • Store trains for loading or unloading. • Store passenger trains not in use. • Allow fast trains to pass slower trains in some areas.
Siding Figure 3 - Siding Direction of travel It is essential that all employees working in the danger zone know which direction trains travel on every line. UP and DOWN trains and tracks Trains running TOWARDS Sydney are UP trains. The tracks that carry them are UP tracks. Trains running AWAY FROM Sydney are DOWN trains. The tracks that carry them are DOWN tracks. When facing AWAY from Sydney: • The UP side or UP track is on the RIGHT. • The DOWN side or DOWN track is on the LEFT.
UP and DOWN rails and the UP and DOWN side When standing in the four foot facing AWAY from Sydney, the UP rail is on the RIGHT. When standing in the four foot, facing AWAY from Sydney, the DOWN rail is on the LEFT.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 9 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
If something is on the LEFT of the track when facing AWAY from Sydney, we say it is on the DOWN side. If something is on the RIGHT of the track when facing AWAY from Sydney, we say it is on the UP side. Fixed Signals are used to control the movement of trains and are normally found on the left hand side of the track in the direction of travel. ie Same side as the driver. Because of where they are placed and how they are numbered they can be used to identify which direction you are facing and which is the Down and Up directions. The last identifying number on the signal indicates the Up or Down direction. ODD number (1, 3, 5, 7, 9) is for the DOWN direction. EVEN number (2, 4, 6, 8, 0) is for the UP direction. (See Figure 4). Even number means the signal is on the left of the UP track
Figure 4 – Signal number Single Lines Single lines have only 1 track. Trains travel in both Up and Down directions on the same track. Double Lines Double lines have 2 tracks: The UP track carries trains travelling TOWARDS Sydney. The DOWN track carries trains travelling AWAY FROM Sydney. Multiple Lines More than two lines ie Mains, Suburbans and Locals. Can be set out in Left Hand Working or Parallel Working. Left-Hand Working In left-hand working the tracks are laid out so that the direction of travel is alternatively in the DOWN direction and UP direction e.g. with your back to Sydney, the down is on the left.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 10 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Country
DOWN Side
UP Side
UP Local
DOWN Local
DOWN Suburban
DOWN Rail
UP Suburban
UP Rail
UP Main DOWN Main
Sydney Figure 5 – Left Hand working in Multiple tracks Parallel Working In Parallel Working there are four tracks. The two UP tracks are grouped together and the two DOWN tracks are grouped together e.g. Up trains on adjacent tracks. Bi-directional Lines In some Double line sections trains may travel on any track, in any direction, at normal speed. Kilometrage This is the track distance from Sydney measured in kilometres. All kilometrages are measured from the buffer stop at No. 1 platform in Sydney Terminal. Kilometrages are shown: • On Survey plaques attached to Overhead Wiring structures or other structures, OR • on posts on the DOWN side of the track, which are known as kilometre posts.
Survey plaque
Figure 6 – Survey plaque
© Rail Corporation Issued June 2012
Figure 7 – Kilometre and half kilometre posts
UNCONTROLLED WHEN PRINTED
Page 11 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
NOTE: Overhead wiring masts also have a structure number attached. They look like the number shown in Figure 8.
Figure 8 – OHW structure numbers When precisely locating track kilometrage, measure from the nearest survey plaque. Use the kilometre figure on the plaque, not the OHWS number. Only use kilometre and halfkilometre pegs when no other reference is available as these locations are not precisely located. Kilometres are referred to by using the decimal point e.g. 34.256Km.
OHW Structure No.
Survey kilometrage This shows 35.316km + 603mm
If you only need to pinpoint the approximate location of track features you can use kilometre posts. You can also use OHW mast numbers but you must state these using the "+" symbol convention e.g. 34+272. Route Kilometrage Is the length of a section of track from beginning to the end in kilometres.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 12 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Track Kilometrage Is the length of a section of track multiplied by the number of tracks. eg. A section of track is 1.5km long with 2 tracks. Route kilometrage = 1.5km Track kilometrage = 2 x 1.5km = 3km. Route kilometrage = 1.5km
2 tracks X 1.5km = 3 track kilometres Figure 9 – Track & route kilometres
C2-3
Other Railway terms
C2-3.1
Signalling The following are parts of the signalling system that track people will come across regularly. They are generally connected to, or very close to, the track. The signalling system controls the operation of trains on the network. If your work on track damages any of this equipment, the safe and reliable operation of trains will be affected. Track staff DO NOT maintain this equipment. immediately for repair by signalling staff.
Any damage MUST be reported
Signals Signals are coloured lights placed next to the track to give train drivers instructions on when to stop and when they can travel at normal speed. They are generally placed on posts (See Figure 11) but may also be close to the ground (dwarf signals -see Figure 10) or attached to structures over the track. Train stops To provide a level of protection against trains travelling past a signal that is at STOP, most of the RailCorp network is fitted with “Train Stops” at signals (see Figure 10, Figure 11 and Figure 12) and RailCorp’s urban, interurban and country passenger fleet are fitted with “trips”. When a signal is at STOP the train stop is in the raised position. If a train passes the train stop, the “trip” will strike the train stop and the brakes on the train will be applied.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 13 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Train Stop
Figure 10 – Dwarf Signal & train stop
Train Stop
Figure 11 – Signal & train stop
Figure 12 - Train stop
Points equipment Mainline turnouts are generally operated remotely (someone sitting in a signalling complex many kilometres away). The points in the turnout are connected by rods to a motor at the side of the track. The motor is operated by hydraulics or electrically to push or pull the rodding, changing the direction of the points (See Figure 13 and Figure 14).
Figure 13 – Points rodding and motor
Figure 14 – Points rodding
Since the turnouts are operated from a long distance away, and the operator cannot see that the points have moved as directed, an electrical detection system is connected to the turnout. If the detection system does not detect successful operation of the points, it will stop trains.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 14 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Track circuits Operators need to know where trains are so that following and opposing movements of other trains can be controlled. To do this, the track in RailCorp is broken into many small track circuits by attaching wiring to either end of the track and passing an electric current through it. When a train wheel passes onto the circuit, it shorts out the circuit and operates the signals. Track circuits are also used to operate Warning lights and Level Crossing lights and bells.
Figure 15 – Track circuit cables
Figure 16 – Rail bonds
Figure 17 – Rail bond welding
Channel iron One method of operating points remotely from signal boxes is by mechanical rodding called “Channel Iron” that is connected from a lever by long rods to the points. You pull the lever at one end, the rods move, and they push (or pull) the points open or closed at the other end. They are restricted in length and are subject to damage. They have mostly been replaced by motor operation.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 15 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Signal troughing
Channel Iron Impedence bond
Figure 18 - Channel Iron
Figure 19 - Impedence bond and Signal troughing
Troughing Some signal circuit wiring is contained above ground in signal troughing. Most troughing has been replaced by buried cables. Impedence bond Impedence bonds are mounted in the “four foot” at some locations to manage conflicts between the electrical track circuits and the return current from the overhead electrical power system.
C2-3.2
Electrical The majority of RailCorp’s network is operated by electrical traction. AC (Alternating Current) power supplied to RailCorp is transformed at electrical substations on the network to 1500 Volt DC (Direct Current) power. This is fed to the overhead wiring system. Pantographs on top of trains come in contact with the “contact wire” carrying the current. The current is directed to electric motors on the train to drive the wheels. Overhead wiring structures The overhead wiring system needed to supply 1500 volt power is heavy. It must also be placed and kept in position fairly close to the centre of the track, otherwise the pantographs will lose the wires. To keep it up and in place, large overhead wiring structures are required. Figure 20 explains some elements of the OHW system. Catenary wire Portal Frame
In-span feeder Droppers
PP mast
Contact wire
Figure 20 – Overhead wiring © Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 16 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Traction return current The 1500 DC power passes from the train through the wheels to the track. This Traction return current passes from the track through wiring to the substation. The wiring is bonded to the outside of the rail head. (See Figure 21). Track staff DO NOT maintain this equipment. immediately for repair by signalling staff.
Any damage MUST be reported
Figure 21 - Electrical rail bonds
C2-3.3
Structures There are many objects built permanently above, below or at the side of the track that are of interest to track staff. These include bridges, tunnels, airspace developments (Car parks and shopping centres), level crossings, cattle stops and buffer stops.
C2-3.3.1
Underbridge This is where the road traffic or waterway goes UNDER the track. (See Figure 22).
C2-3.3.2
Overbridge This is where the traffic goes OVER the track. (See Figure 23).
C2-3.3.3
Footbridge This is an overbridge used by pedestrians to cross the track or gain access to a station platform.
Figure 22 - Underbridge
© Rail Corporation Issued June 2012
Figure 23 - Overbridge
UNCONTROLLED WHEN PRINTED
Page 17 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
C2-3.3.4
TMC 202
Structure guard rails The purpose of a guardrail is to keep derailed bogie/wheels tracked parallel to the running rails. This action prevents a derailed train hitting adjacent infrastructure or falling off a bridge. Guardrails are required on certain types of underbridge, on track at or near structures supporting air space developments and at other high risk locations where a derailment could cause severe problems. Guard rails are made from at least siding quality rail and are placed between 200mm and 380mm from running rail. They are fastened using the same fastenings as running rails. Concrete guard rail sleepers are manufactured with extra lugs/seats for guard rail fastenings. A tapered nose (“V”) extends 3.6m beyond the abutment on the approach side with the guard rails extending 3m beyond abutment on the departure side. Special designs needed for areas with expansion joints or noise/vibration plates. Special care is needed to make sure that track circuit and traction return current are not short circuited.
Figure 24 – Guard rails
C2-3.3.5
Level crossings These are where roads cross the tracks at the same level as the running surfaces of the rails.
Figure 25 – Level Crossing © Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 18 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
At level crossings, a protected flangeway is provided as a guide for the wheel flange and to keep the road surfaces from the rails. Checkrails can be made from rail or steel angle section and should have splayed ends to ensure wheels not tracking correctly are led into the flangeways. Precast concrete and rubber panel crossings generally have flangeways built into the design.
C2-3.3.6
Buffer stops These are structures placed at the dead end of a siding. They stop movement when the vehicle buffers come into contact with them.
C2-3.3.7
Cattle stops These are grids made of rails to stop cattle or livestock from entering another paddock where the track passes through the fence.
C2-3.3.8
Fencing All railway lines in the state were constructed by permission of separate Acts of Parliament. These Acts stated whether the line would be Fenced or Unfenced. All lines in RailCorp are Fenced lines. On fenced lines the person constructing the line must provide and maintain fences to: Distinguish railway land from other land. Prevent any person from trespassing on railway land. Prevent stock (animals) from straying onto the line. RailCorp has a responsibility to maintain a stock proof fence on the boundary of all fenced lines and must pay compensation for stock that is killed or hurt if the fence is defective. All gates on fenced lines are part of the boundary fencing. They must be kept closed and locked at all times. Gates that cannot be properly closed must be repaired or replaced. Standard fencing includes 1.
6 Strand Wire Fence - This type of fencing is used in rural areas. It is made of: o Old rail straining panels with steel star posts. o Four plain and two barbed galvanised wires.
2.
C2-3.4
Chain Mesh or Weld Mesh - These types are usually used in Metropolitan or Urban areas.
Train Inspection Sites RailCorp has a number of train inspection sites throughout the rail network. These sites monitor (or inspect) passing trains and detect and report on various parameters of the train.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 19 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Track staff DO NOT maintain this equipment. Any damage MUST be reported immediately for repair by the Train Monitoring Systems Unit (TMSU). The following Train inspection sites are in use in the RailCorp network.
C2-3.4.1
Automatic Equipment Identification (AEI) Readers Automatic Equipment Identification (AEI) Readers read identifying information from passing locomotives and wagons. This allows the movement of rolling stock to be tracked as it traverses through the network. The identifying information is contained in AEI tags attached to each locomotive and wagon belonging to all major operators within NSW. Each AEI installation consists of AEI antennae per track, wheel sensors to detect the presence of a train and control equipment. High mount AEI antennae are normally mounted on posts alongside the track. Low mount AEI antennae are normally mounted on the end of sleepers on an adjacent track. Wheel sensors and Presence loops (where used) are bolted or clamped to the track.
Figure 26 - High mount (left) and low mount (right) Automatic Equipment Identification Readers
C2-3.4.2
High Speed Weighbridge Sites High speed weighbridges collect data on the weight of passing trains. High speed weighbridges are capable of accurate weighing of trains travelling up to 80km/h. Each weighbridge consists of wheel sensors to detect the presence of a train, record the number of axles on the train and measure the speed of each wagon, strain gauge transducers mounted in the web of each rail and control equipment, to process and store the data collected. Wheel Sensors are bolted to the track. The Strain Gauge Transducers are integral to the portion of rail on which they are installed, which in turn is welded into the track.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 20 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Figure 27 - High speed weighbridge installation
C2-3.4.3
Figure 28 - Hot Box Detector / Hot Wheel Detector installation
Hot Box / Hot Wheel Detector Installations A Hot Box Detector (HBD) detects overheated axle bearings on rolling stock as trains pass an installation site. An overheated axle bearing (hot box) is an indicator of a damaged bearing and is often a precursor to a critical failure of the bearing. A HBD consists of hot box detector scanners, one for each side of the track and an array of wheel sensors to detect the presence of a train. Hot Wheel Detectors (HWD) are an add-on to a HBD to detect overheated wheels and brakes on rolling stock. HBD/HWDs and associated equipment are normally clamped to the rail or are mounted on sleeper ends outside the four-foot.
C2-3.4.4
Dragging Equipment Detector A Dragging Equipment Detector (DED) monitors passing trains to ensure that there are no dragging chains or other equipment that may cause damage to trackside structures such as signals and points, as well as trains on adjacent lines. A DED consists of contact closures mounted across the track (approximately spanning the length of the sleepers) attached to sleepers.
Figure 29 - Dragging Equipment Detector
© Rail Corporation Issued June 2012
Figure 30 - WILD array
UNCONTROLLED WHEN PRINTED
Page 21 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
C2-3.4.5
TMC 202
Wheel Condition Monitoring (WILD) Detector A WILD detector monitors the condition of wheels as trains pass over an installation site. A WILD measures the force of impact on the track caused by each wheel in a train consist. In doing this, a WILD can provide early detection of wheel defects such as skids (i.e. wheel flats), cracks and wheels out-of-round. A WILD consists of arrays of accelerometers and train presence switches clamped to the rails, and control and processing equipment installed in a hut adjacent to the arrays and at remote sites.
C2-3.5
Trip Gear Magnets Retractable train trips are installed on XPT, Xplorer and Endeavour trains. The trips are needed to operate in conjunction with trip arms in the Metropolitan area. The trips are not, however, required in the Country area. To reduce the potential for damage to the trip mechanism and unnecessary emergency brake applications, an induction system, using track magnets, has been installed to raise and lower the trip gear when it leaves or enters the Metropolitan area. To raise or lower trip gear, two pairs or “sets” of magnets are attached to sleepers in the 4-foot at set distances. (See Figure 31). One pair, the South Pole magnets, are coloured BLUE, and LOWER the trip gear. The second pair, the North Pole magnets, are coloured YELLOW, and RAISE the trip gear. South Pole magnets are ALWAYS on the Sydney side of North Pole magnets. Magnets are set at rail level and attached with epoxy to concrete sleepers or coach screwed to timber sleepers. In addition, at each location, signs have been erected trackside to alert the driver when the Automatic trip gear is lowered or raised. Health Warning signs have also been erected to warn of the hazard to people with heart pacemakers. If any magnets or signs are missing or damaged, they should be reported to the Team Manager for replacement within 24 hours. If replacement magnets cannot be installed within 24 hours the maintenance supervisor is required to notify the signaller by reporting the location and track. The signaller will inform the train driver, who is able to take action to manually raise or lower the trip gear. This is not a desired option and is only be used in an emergency situation of magnet shortage.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 22 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Country
North Pole magnets Raise the Trip when train travels in this direction
Figure 32 - South magnet assembly on concrete sleeper
South Pole magnets Lower the Trip when train travels in this direction
Sydney Figure 31 - Complete Trip Magnet Assembly
C2-3.6
Figure 33 - North Magnet assembly on Concrete sleeper
Survey marks In order to know exactly where to place a railway track, surveyors use sophisticated measurement techniques to place permanent marks near the track. These marks are close enough for track staff to be able to measure from the mark to the track. Surveyors use two levels of control marks in their work. Survey Control Marks Survey Control Marks are established on a broad grid (generally about 500m apart) along the rail corridor. They are sometimes installed by RailCorp, in which case they will be RailCorp Survey Marks (RSM) but mostly they are official State Survey Marks or Permanent Marks that can be used by non rail surveyors for their survey work. Examples of these marks are shown in Figure 34 to Figure 37.
Figure 34 - NSW Permanent Mark (PM) on Platform
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 23 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Figure 35 - RailCorp Survey Mark on Platform
Figure 36 - NSW State Survey Mark (SSM)
Track Control Marks The framework of the Survey Control Marks is used to establish Track Control Marks at short intervals along the track (generally no more than 20m apart). The design location (horizontal and vertical) of each track is determined as a distance from each Track Control Mark and is recorded by the surveyors. In most cases this information is engraved on a Survey plaque that is placed at the mark. (See Figure 38 to Figure 40). This is the most accurate information of the design geometry of the track and is used by track staff to check and correct track alignment, level, superelevation and track centres. It is also used when determining the official kilometrage of the track.
Figure 37 - RailCorp Survey Mark on Platform
Figure 39 - Track Control Mark and Survey Plaque
© Rail Corporation Issued June 2012
Figure 38 - Track Control Mark and Survey Plaque
Figure 40 - Track Control Mark
UNCONTROLLED WHEN PRINTED
Page 24 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Track Control Mark is for this track OHW Structure No.
This TCM is on a platform face (Platform 6 Central)
kilometres Survey kilometrage
metres millimetres
Distance between tracks Superelevation
Distance from TCM to gauge face of nearest rail Distance from TCM to top of low rail
Figure 41 - Survey Plaques
C2-4
Dictionary of track terms Term
Description
A Actual Measured Rail Temperature
The measured temperature as recorded when measuring rail gaps.
Alignment
The horizontal position of a track measured in relation to survey marks. The measurement of alignment is from survey marks to the line rail.
Alignment Index
The ratio of Curve Radius (m) to length of the Curve (m). Used in the calculation of track stability.
Aluminothermic Welding
Field welding by any process using an Aluminothermic type reaction.
Aluminothermic Welding Gap
The gap required between the rail ends to be welded together by aluminothermic welding.
Anchor Point
A section of track in which the rails are anchored to ties or bearers to prevent any longitudinal rail movement. The securely anchored track section provides a stable platform for managing rail stress adjustment.
Approved track components
Products approved for use on RailCorp track infrastructure.
B Ballast
Free draining coarse aggregate or metallurgical slag used to support railway tracks.
Ballast Cleaning
Process for removing fines from in-track ballast by removing the ballast from the track, sieving it and returning graded ballast to the track in a continuous operation. Often includes addition of new ballast.
Ballast Depth
Distance from the formation level to the base of the sleeper below the lowest rail seat.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 25 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Term
Description
Ballast Shoulder Height
Height of the shoulder ballast above the sleeper base as measured at the end of the sleeper.
Ballast Shoulder Width
Width of the shoulder ballast as measured from the sleeper end to the edge of the shoulder.
Base Operating Limits
The limits of track conditions outside which operating restrictions will apply.
Bearer
A type of sleeper used under points and crossing track structures. Bearers are generally larger in dimension than standard sleepers to provide support for both tracks as well as the increased loading experienced under such track structures.
Beater Packing
Process for tightly packing ballast under sleepers using manual methods (includes hand tools and small motor driven machinery).
Bend
The point of intersection of two straights.
Bonded Insulated Joint
A pre-assembled rail joint consisting of rail sections connected by high-strength, purpose designed fishplates and connecting bolts reinforced by a high-strength, insulating bonding material. The joint provides electrical insulation between the connected rail ends via the insulating resin.
Box anchor
Application of four (4) rail anchors to a sleeper, that is, two (2) to each rail with one on each side of the sleeper.
Boxing Up
Process for establishing correct ballast profile by laying ballast in sleeper cribs and on shoulders.
Buckle
See “Misalignment”.
C Cant - Rail
The inclination of the base of the rail relative to the sleeper base.
Cant - Track
See "Superelevation"
Cast in shoulder
A component in concrete sleepers and bearers that prevents lateral movement of the rail foot and provides anchorage for the resilient fastening system.
Cast- in synthetic Insert
A component in concrete bearers that allows a screwspike to provide lateral restraint for turnout switch plates.
Catch points:
A single switch assembly and a throw-off rail. The catch point switch is normally set in the open position, thus breaking the continuity of the siding track causing unauthorised train movements to derail at a point clear of the main line.
Chair Plates
A flat plate with a pressed up section that is attached with a bolt through the web of either stockrail, in the case of a switch assembly, or the checkrail carrier, in the case of a checkrail assembly. The types of chairs are identified by a mark on the end of the plate.
Checkrail
A rail placed inside the running rail which comes into contact with the back of the wheel flange and is used in points and crossing work to provide steering of the wheelset such that the crossing nose is not contacted by the opposite wheel.
Checkrail Effectiveness
Distance from the guard face of checkrail to the gauge face of the nose of crossing, measured square to the running rail at the nose of the crossing.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 26 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
Term Checkrail Unit
TMC 202
Description The unit consists of a length of rail (called the checkrail) with a flared bevel machined on each end, hardened on the checking face, bolted through chocks to a closure rail (called the carrier) to attain a flangeway clearance. The centre of the checkrail is usually opposite the theoretical point of the crossing.
Chocks
An iron casting used mainly with checkrails and crossings to support rail components at a fixed distance apart. Raised lettering and numbers on the chock identify its application
Circular Curve
Component of horizontal or vertical track alignment, defined by end points and radius.
Clearance
The space margin between the kinematic envelope of rolling stock and a structure, or between rolling stock on adjacent tracks.
Clearance Point
A point on converging or diverging tracks where the track centres or separation between the tracks allows clear passage for passing trains and beyond which vehicles must not stand.
Closure
A short length of rail used to replace a piece of rail in track. A closure is not generally less than 2.2m long except in turnouts where special requirements may apply.
Closure Rails
Rails making up a turnout apart from those in the points, crossings and checkrail units.
Combined Rail wear
Rail wear that includes both curve (side) and tangent (top wear).
Compound Manganese Crossing
Comprises a crossing V point that is manufactured from a cast manganese nose which is explosively hardened and flashbutt welded to head hardened rails to complete the V which replaces the point/housed rails in a fabricated crossing.
Compound Transition
The component that joins two circular curves of different radii.
Compression
When rail temperature is increased the rail expands and there are no available gaps to allow the rail to freely expand. The force generated will place the rail in compression.
Continuous Welded Rail (CWR):
Track where the rail is joined by welding (and other non-moveable joints such as glued insulated joints) in continuous lengths between fixed points or in lengths greater than 220m, and where adjustment controls are in place.
Corridor Transit Space Strategy:
Operating parameters for a specified line, incorporating business and infrastructure service requirements.
Cracking or spalling of the rail head:
surface damage in the form of visual cracks or breakout of small shallow sections of the rail surface typically 3mm to 6mm in depth.
Creep control point:
A reference marker recording the position of a rail at the time of stress adjustment and subsequent longitudinal movement.
Crib Ballast
The track ballast located between adjacent sleepers.
Cross Level
The difference in level of the two rails in a track.
Crossing Assembly.
The component of a track system where lines branch out or intersect. Crossings assist in the passage of track wheels where two track rails intersect. Crossings may be fixed or switchable.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 27 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Term
Description
Crossover
The means by which trains pass from one track to an adjacent parallel track. A Crossover is constructed from two turnouts (one on each track facing opposite directions) and connecting plain trackwork.
Curve Creep
Expressed in terms of equivalent tangent creep, curve creep expresses the increase or decrease in “rail stress” due to the radial movement of curves in a half kilometre section.
Cutting
Excavation of the natural ground to a determined cross section and longitudinal profile to accommodate the railway and any associated infrastructure.
D Defined event
The specific conditions which cause a special location to be at a higher than acceptable risk.
Derail
A vehicle derailing device that, when operating to protect the main running line, causes wheels to climb the siding rail and derail clear of the protected line.
Detailed Walking
A thorough examination, by walking, of the components of the track structure and the right of way, to ensure that the components are satisfactory and contribute to a safe railway.
Diamond Crossing
The component of a track system where lines intersect. Diamond Crossings comprise V and K crossings.
Dogspike
A round spike that is driven into a pr-drilled hole in a sleeper to hold the rail foot against vertical and lateral movement.
Double Glued Insulated Joint
A pair of glued insulated joints installed adjacent to each other on a running rail.
Drainage
The surface flow of water away from the track structure and cess. It includes: − Top and side drains along the railway reserve to direct water away from the rail track formation to recognised water courses. − Pipes installed expressly to collect water from between or beside tracks and direct it away to a recognised side drain or watercourse. − Waterways constructed under the track, whether pipes, culverts, or similar.
E Effective sleeper
When the sleeper and fastenings combine to effectively support the rails vertically and provides lateral restraint. Restraint must allow no lateral movement of the fastenings relative to the timber. The sleeper must provide gauge restraint and must be one piece that will not separate along its length or transversely. Sleepers should not be excessively backcanted more than 1 in 30. Timber sleepers with rot, or holes through which ballast can be seen are not satisfactory. At least 300mm is required between rail foot and sleeper ends for effective tamping.
Elastic fastenings
See “Resilient Fastenings”
Embankment
Stabilised fill formation, above the natural ground, to a determined cross section and longitudinal profile to accommodate the railway and any associated infrastructure.
Exceedent
A variation from maintenance or operating standards which exceeds nominated limit (also known as a defect).
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 28 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
Term Expansion switch:
TMC 202
Description An assembly comprising two rails appropriately matched and fastened at the longitudinal interface to provide virtual continuity of the running rail and gauge faces while allowing controlled longitudinal slip. Expansion switches provide a level of control for rail stresses when tracks are attached to sub-structures (eg steel underbridges) which are also subject to temperature related expansion and contraction.
F Fabricated Crossing
Comprises a Vee and two (2) wing rails fabricated from sections of rail, set, machined and fitted together with chocks. The hand of the crossing is determined by the location of the point rail and may be right or left. The point rail is always the rail carrying the maximum tonnages, or higher speed. A right hand crossing has the point rail in the rail that connects to the right hand switch.
Face work
Where sleepers are replaced systematically one after another.
Field Assembled Glued Joint:
A rail joint consisting of bored rail ends, high-strength purpose designed fishplates and connecting bolts reinforced by an insulating epoxy resin mixed and applied in the field. The joint provides electrical insulation between the connected rail ends via the insulating resin.
Field Welding
Welding of rails together in the track by any process.
Fishbolts
Bolts shaped to fit through fishplates to provide a mechanical rail joint.
Fishplates
Mechanical joint components shaped to fit against the head, web and foot of a rail and by means of 6 fish bolts provide a structural support to give a continuous running rail section.
Fishscaling:
The flow of steel at the gauge corner of the rail that resembles a series of fishscales.
Fixed crossings.
These crossings have a wheel flange gap in both rails. Wheel transfer at fixed crossings depends on matching wheel and rail profiles. Fixed crossings are used in conjunction with check (guide) rails to provide lateral guidance in the crossing area.
Fixed point
A point or location in the track where the rail is fixed and cannot move longitudinally relative to the sleepers and ballast. This may include such locations as turnouts, level crossings and transition points from dog spiked timber sleepered track to resilient fastened concrete sleepered track.
Flame Cut Rail-
A rail closure fastened at a mechanical joint where the rail end(s) have been cut or bolt holes have been blown by a gas cutting process.
Flangeway
The space adjacent to the gauge face of a running rail to allow for the passage of wheel flanges.
Flangeway Clearance
The distance between the gauge side of a running rail and the guard face of a check rail or the guard face of a wing rail.
Flangeway Depth
Flange way depth is the height of the running surface of the rail above the top of the blocks at check rails and in ‘V’ and ‘K’ crossings.
Flexible Switch
A switch machined from longer rails and fixed towards the end of this rail with blocks to the adjacent stockrail. The switch movement is provided by the flexibility of the longer switch rail and a section machined from the rail foot towards the fixed end.
Foul Ballast
Ballast that has been contaminated by degraded ballast fines, fines from failed formation and/or deposited material. Free drainage has been blocked.
Free Welding
Welding without correcting rail adjustment.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 29 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
Term
TMC 202
Description
French Rail
Rail branded “Longwy” or “Micheville”, installed in the 1950's and exhibiting severe internal defects.
Front of Train Examination
A non specific examination which assists in the assessment of track by enabling the reaction of trains to the track structure to be observed (preferably at maximum allowable speed).
Frozen Rail Joint
A joint that is not free to open and close with changes in rail temperature.
G Gauge
The distance between the inside running (or gauge) faces of the two rails measured between points 16mm below the top of the rail head.
Gauge corner fatigue:
Damage to the gauge corner of the rail in the form of longitudinal cracks and dark spots irregularly spaced in the gauge corner. It may also take the form of fishscaling or lamination.
Gauge face angle
The angle of the gauge face to the vertical.
Grade Rail
The rail that defines the vertical position of the track. On curves, the low rail is the grade rail. On tangent track either rail is the grade rail.
Graded Rail Level
The designed rail level for the track.
Guard Rail
A rail (inside or outside the running rail) used to restrain lateral movement of a derailed wheelset. Used to protect structures or control the lateral movement of the wheelset on bridges or in other higher risk situations.
H Heeled Switch
A switch that pivots about a gapped joint between the switch rail and adjoining closure rail. The switch is bolted to the stockrail and closure rail using a heel block and fishplate designed to allow this movement.
Horizontal Alignment
The designed horizontal location of track as measured to survey marks.
Housed Switch
A heavy duty switch and joggled stockrail equipped with a “Housing”. The housing is a specially machined component with a hardened checking face fitting above the switch to act as a checkrail for the opposite switch and joggle. Where both switches are required to be heavy duty a housing is required on one of the switches.
I Insulated Plate Joint:
An assembled joint consisting of bored rail ends, joined with purpose designed joint plates that are electrically insulated at all external surfaces and connected to the rail by high tensile bolts or swage fastenings.
Insulated Rail Joint
A rail joint designed to prevent the flow of signalling circuit currents across the rail ends. Generally this is achieved by using insulating materials to separate the steel components of the mechanical joints.
J Jointed Welded Rail (JWR)
Rails which are, individually, longer than 27.4m and less than or equal to 220m. Rail adjustment can be calculated from gap measurement. Rail fastenings comprise dogspikes and anchors or a mixture of dogspikes and resilient fastenings no greater than 1 resilient fastening in 3.
Junction Rail:
A rail with differing rail profiles at each end in order to match with rails of dissimilar section.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 30 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Term
Description
K K Crossing
The principal special component of a diamond crossing. It is the intersecting component between two rails. The intersection creates an unchecked area in the centre of the K, thus limiting the angles that can be designed for K crossings.
Kinematic Envelope
A two dimensional cross-sectional representation of the swept path of a rail vehicle.
Kinematic Outline
A two dimensional cross-sectional representation of the swept path of all the vehicles authorised at a particular location.
L Lading
The clearance outline of cargo carried on or in vehicles, including any fastening systems.
Lamination:
The formation of thin layers of metallurgically altered steel near the rail surface that typically interfere with ultrasonic signals used for rail examination.
Level Crossing
A structure provided at track grade to enable vehicular and/or pedestrian traffic to cross rail lines.
Line
The smoothness of the horizontal location of the track. The method of measurement is by stringlining methods. Note the comparison with alignment. Track can have good line (ie be straight or have a smooth curve) but have poor alignment (offset from design position). Conversely track can have good alignment (on design position at the survey marks) but poor line (not smooth line in between the marks).
Line Rail
The Rail from which line is measured. This should be the outer rail of curves. On tangent track either rail can be used but the same rail shall be used throughout the tangent.
Lockspike
Spring fastening spikes used to secure sleeper plates to timber sleepers. They are driven through holes in the sleeper plate into the timber sleeper. As the spike penetrates the timber, the points of the spike separate and anchor the spike into the sleeper.
Long Welded Track (LWR):
See “Jointed Welded Rail”
Loose rail
Track in which rails are 27.4m or less.
M Main lines
Main running lines crossing loops, refuge loops and sidings with a maximum permissible speed greater than 25km/hr.
Major Cyclic Maintenance
Resurfacing, Ballast cleaning, rerailing, formation reconditioning.
Manual Point Lever:
An apparatus consisting of a manually actuated lever and connecting rodding to operate points in turnouts and catchpoints or to operate a derail device. Manual point levers do not include ground frame or signal box levers that are generally connected to an interlocked signalling system.
Manual Resleepering
Replacement of sleepers using hand held tools and equipment and small on or off track plant.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 31 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Term
Description
Mechanical Insulated Joint:
A conventional joint assembly where the components and insulation material are fitted to a modified mechanical rail joint. They can be dissembled to their component parts. They may include Standard Mechanical Insulated Joints or Insulated Plate Joints.
Mechanical Joint.
A conventional joint assembly comprising fishplates, fishbolts and washers, that can be, dissembled to its component parts. [Mechanical joints allow for some limited movement of the rail ends.]
Mechanised Resleepering
Replacement of sleepers using dedicated teams and large production plant.
Misalignment
A sharp horizontal displacement of track (includes rails and sleepers). A misalignment occurs when the compression generated in the rails exceeds the ability of the structure to hold itself in place and the track is displaced laterally. Irrespective of the resulting horizontal displacement a misalignment has occurred when there is visible evidence that the sleepers have moved laterally in the ballast.
Monoblock sleeper
Prestressed concrete sleeper cast in a single piece.
N Neutral Rail Temperature
See “Neutral Temperature”
Neutral Temperature:
Rail temperature at which rail is stress free. The track shall be adjusted so that this will occur at 35 C.
Nominal Size
The designation of an aggregate which gives an indication of the largest size particle present.
Non Standard Welded Track
Track that does not conform to the definition of Standard Welded Track. It is track for which rail adjustment cannot be assessed with confidence and comprises
Non-elastic fastenings
-
rails longer than 220m which have not been adjusted
-
rails longer than 220m with no creep marks or pegs
-
rails longer than 220m with no alignment information available
-
rails longer than 27.4m with resilient fastenings more than 1 in 3 (unless the rails have been correctly adjusted in accordance with requirements for CWR) Fastenings that allow no vertical movement of rail. Dogspikes are non-elastic fastenings.
O Open Ballasted Track
Track comprising of rails, fastenings, sleepers and ballast. It does not include track comprising of slab or embedded systems, or track on transom deck bridges.
Operating Limit
The limit or condition which triggers a mandatory response. The response depends on the asset and its condition and may require restricting operations or reviewing whether operational restrictions are required.
Operating Restriction
A restriction on the operation of rolling stock (such as speed, axle load, type of rolling stock, time of operation) to provide an appropriate level of risk in response to a specific infrastructure condition.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 32 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Term
Description
P Permanent rail joint
Non-welded rail joints intended for use in track in the long term. They include fishplated joints, bonded insulated joints and expansion joints.
Points and crossings
In track structures that provide for one track to join or cross another whilst maintaining continuous support and direction to the rolling stock wheels. The points are the location where one track separates into two tracks (or vice-versa) and generally includes moving rail components called switches or switch blades. The crossing allows rolling stock wheels to cross over a rail. Combinations of points and crossings may be used to construct various track structures including slips, diamond crossings, turnouts and catch points.
Points Assembly
The location where one track separates into two tracks (or vice-versa) and generally includes moving rail components called switches or switch blades that are attached to stockrails.
Prestressed concrete bearer
Concrete bearer where the deformed reinforcing bars (tendons) are stressed before casting the concrete
Prestressed concrete sleeper
Concrete sleeper where the deformed reinforcing bars (tendons) are stressed before casting the concrete.
Partial Resleepering (PRS)
Replacement of sleepers in a pattern or at random to maintain a general sleeper condition in a track section.
Q
No entries
R Rail Adjustment
The procedure used to ensure welded track is in a “stress free” state at the defined neutral rail temperature.
Rail Anchors:
Devices (other than resilient fastenings) interfacing between a rail and the supporting ties or bearers designed to prevent longitudinal movement of the rail relative to the ties.
Rail Brace
Component used in points assemblies to fasten the stockrail in position where fastenings on the gauge side of the rail cannot be used. The Rail Brace contacts the underside of the head and the top of the foot of the stockrail and is used for stockrail support to maintain the gauge.
Rail Brace Plates
Attach the Rail Brace to the bearer. The plates are distinguishable by a number at the end.
Rail Bunching
Rail Creep towards a fixed point, resulting in increased compressive stress.
Rail corrugations:
Cyclic wave defects that form on the surface of the rail. There are two types viz. short pitched about 30mm to 90mm wave length with a characteristic regular sequence of bright peaks with darker hollows on the running surface and long wave length around 300mm pitch with depressions in the running surface. There is no difference in appearance between peaks and hollows for this category.
Rail Creep
The longitudinal movement of rail through the fastening system.
Rail Defects
Rail discontinuities greater than the minimum size and for which there is a defined repair response.
Rail End Batter
A permanent plastic deformation of a rail end at a joint resulting from wheel impacts.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 33 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
Term
TMC 202
Description
Rail Gap Dial Calculator
Rail Gap Dial Calculator is a round slide rule type calculator using rail temperature and rail length to give appropriate rail gap for a neutral temperature of 350C. For use with CWR work only.
Rail Gaps
Space between rail ends in jointed track.
Rail Level
The rail level when measured on the head of the rail. The down rail on straight tracks. The low rail on curves.
Rail Lubricator:
A device attached to a running rail designed to apply a controlled volume of lubricant to passing wheel flanges, which transport and deposit the lubricant on the high rail of curves to reduce friction and rail/wheel wear.
Rail or Running Rail
A rolled steel section installed in the track and fastened to gauge for the purpose of carrying railway traffic.
Rail side (curve) wear
Rail wear that normally occurs in the high leg of curved track and has only a minimal amount of top wear. Side wear can be measured either by determining the width of the rail 16 mm below the running surface in mm, or the loss of head area as a percentage of the original head area.
Rail Temperature
Temperature recorded on web of rail on its shaded side.
Rail Temperature Error
An expression of rail adjustment in 0C indicating the extent of rail adjustment deviation in relation to the standard neutral temperature (350C). It is calculated by subtracting the Theoretical Measured Temperature from the Actual Measured Temperature.
Rail top (tangent) wear
Rail wear that normally occurs on the top running surface of the rail in tangent track or the low legs of curves. Usually has a minimal side wear component. Rail tangent wear or top wear shall be measured 16mm in from the running face of the rail.
Rail Wear
Abrasion of rail due to contact between rail and rolling wheels. It occurs as top (tangent) wear or side (curve) wear.
Resilient Baseplates
A device for securing rails to sleepers, transoms, tunnel inverts or track slabs. The fasteners are required to moderate noise and vibration. The baseplates typically consist of a resilient material bonded to a lower frame and rail base.
Resilient Fastenings:
Elastic steel clips attached to ties or bearers and designed to engage rail flanges with a degree of elasticity between the sleeper and rail with the aim of avoiding the loosening of the fastening due to vibration. These clips fasten rails to the ties or bearers providing lateral support. Standard resilient fastenings also generate toe load at the rail flange providing resistance to longitudinal movement. For special applications where longitudinal rail anchoring is not desirable, resilient fastenings may be designed for zero toe load.
Right of Way
The area of land extending to the railway boundaries.
Rolling contact fatigue:
Deep seated cracking that occurs on the rail head due to high contact stresses between wheel and rail.
Rolling Stock
Any vehicle which operates on or uses a railway track, including any loading on such a vehicle, but excluding a vehicle designed for both on- and off-track use when not operating on the track.
Rolling stock Outline
The combination of rolling stock cross-section, bogie centres (or wheelbase for non-bogie rolling stock) and body overhang, and rolling stock tolerances, which define the swept path of the rolling stock.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 34 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Term Rolling stock Tolerances
Description The possible/allowable displacements of the rolling stock from the design rolling stock outline centred on the guiding wheels. These are described in terms of translations and rotations of rigid bodies relative to infrastructure.
S Safety Clearance Margin:
The defined clearance beyond the kinematic envelope necessary for safe operation using specified track and rolling stock tolerances.
Service Requirement:
The clearance beyond the Safety Clearance Margin that enables defined service tasks to be undertaken.(eg walkways between tracks, access roads etc).
Shielding:
When ultrasonic testing of the rail for defects is inhibited by physical or metallurgical alteration to the rail on the surface of the rail head.
Short Rail
See “Loose Rail”
Shoulder Ballast
Ballast placed outside the end of sleepers
Sidings
All operating lines which are not main lines.
Single/Double Slip
A special track layout that combines turnouts and diamond crossings. They allow train movements both across and onto and out of a track.
Sleeper Plates
Steel plates that are fastened on the top of a timber sleeper and onto which rails are placed. In open track they are sloped to provide the rail base with a 1 in 20 cant.
Sleeper Spacing:
The distance between the centrelines of adjoining sleepers.
Sleepers
Timber or concrete planks of defined dimensions that are spaced at intervals on the ballast and on which rails are laid and fastened. They provide the method of fixing track gauge and transferring vertical, lateral and longitudinal loads to the ballast.
Special Loads/Profiles
Vehicle/loading envelopes that infringe approved rolling stock outlines.
Standard Welded Track
Track on which rail adjustment can be measured by the methods available to track staff (ie. gap measurement, creep measurement, alignment measurement) and, for which, ‘as installed’ reference information, where required, is available. Standard Welded Track includes Jointed Welded Rail (JWR) and Continuously Welded Rail (CWR).
Stockrails
These provide support for the closed switch and become the running rail when the switch is open.
Stress free
The rail is in neither tension nor compression. ie the steel is totally relaxed.
Stress free temperature
See “Neutral Temperature”
Structure Gauge
The transit space outline setting out the space parameters necessary for the construction and maintenance of structures adjacent to a rail track.
Summer Period
For hot weather instructions this is defined as 1st November to 31st March.
Superelevation
The vertical distance that the outer rail is raised above the inner or grade rail. See "Cant".
Surface
The relationship of opposite rails to each other in cross level and profile.
Swaged Fastener
High tensile, high clamping strength bolts and fastenings that may be used as replacements for conventional fishbolts for specified applications.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 35 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Term
Description
Swept Path
The maximum three dimensional volume taken up by a specified rolling stock Outline (including rolling stock tolerances) as it moves along a track at specified track tolerances, through design curves, transitions etc.
Swing Nose Crossing
See “Switchable crossings”
Switch Stops
Switch Stops are bolted to the web of the stockrail and make contact with the web of the switch when the switch is in the closed position, providing lateral support. They can be manufactured from castings, rolled angle section or extended bolts.
Switchable crossings.
Also known as Swing Nose Crossing. These crossings close the gap in one track that is being made active for traffic allowing a continuous surface for the wheel to run through the crossing. Wheel transfer in switchable crossings is without any impact for any wheel profile. Switchable crossings have no flange gap in the active track and thus do not require checkrails.
T Tangent Creep
The longitudinal movement of rail in a track section in CWR track. It is generally measured as the net movement into our out of a defined section.
Tangential Switch
A switch manufactured from an asymmetric rail section that is flashbutt welded to a normal rail section towards the fixed end of the switch.
Temporary rail joint
Non-welded rail joints intended for temporary joining of rails only, and generally requiring special measures to be implemented with their use. These measures permit the short-term passage of trains and may include special inspections or speed restrictions.
Tension
At low rail temperature the rail contracts and joint gaps are fully opened placing the rail in tension.
Top
Vertical alignment of the rails.
Track Clearance
The space margin between the kinematic envelope of approved rolling stock and a structure, or between rolling stock on adjacent tracks.
Track Condition Index
A numerical evaluation of track geometry condition used to establish and compare standards of track.
Track Examination System
A group of examinations of the track and right of way which are carried out on a scheduled basis.
Track geometry
The horizontal and vertical alignment, cross-level and superelevation of the track.
Track Stability Loss
Estimate of the vulnerability of a track section to misalignment (or curve pull in) due to variance in rail adjustment and loss of resistance to lateral movement. It is calculated by assigning % values to a set of negative factors (rail adjustment, ballast profile, disturbance, condition etc).
Track Tolerances
The possible displacements of the track from its design track position and gauge.
Trailable Point Lever:
A manual point lever that is designed to allow for vehicle wheels trailing through points set the wrong way to re-set the points for the trailing movement without the need to operate the lever.
Transit Space:
A clearance envelope that provides for the safe passage of defined rolling stock and for infrastructure service requirements. The envelope is defined by a Transit Space outline referred to as 'Structure Gauge'.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 36 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Term
Description
Transition
A track component which joins a straight to a circular curve or connects circular curves of different radii. The transition is based on a cubic parabola.
Transom
Transverse members of track-supporting structures generally made from timber, to which the running and guard rails are fastened. These members are designed specifically as structural members of the track-supporting structure and should not be treated as sleepers.
Turnout
Special trackwork that allows trains to pass from one track on a diverging path. It consists of switch and stockrail assemblies, a 'V' crossing and checkrails, linked together by straight and curved infill rails (closure rails).
Turnout Rail
This is a closure rail that joins the turnout switch to the crossing, as part of the secondary track. It may consist of more than one rail length.
Twist
The variation in actual track cross level between two locations separated by a nominated distance (along the track).
U Underbridge
Support the track and pass over waterways, roadways, pathways etc
Underground Services:
Pipes, cables and other services facilities located underground which may include signalling cables, electric power cables, communications cables, water pipes, drainage pipes, sewerage pipes, gas and other fuel supply lines.
V V crossing
A unit that allows a train travelling on the turnout direction rail to cross the mainline rail. The crossing rate is a measure of the angle made by the main line and turnout rail gauge faces that intersect at the theoretical point. The crossing rate is the cotangent of the angle made.
Vibration Isolating Track Fasteners
See “Resilient Baseplates”
W Wheel burns:
Damage to the surface of the rail in the form of sharp dips or head flow caused by continuous slip of locomotive or multiple unit traction wheels. Damage can be from abrasion or from heat generation.
WOLO Speed Restriction
Temporary reduction in the speed of trains, for one day only, when the AIR temperatures is forecast to be high. Note: WOLO is not an abbreviation for anything. It was originally a 4 letter telegraphic code.
WTSA
Welded Track Stability Analysis – used to assess potential for track to misalign in hot weather
X, Y, Z
No entries
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 37 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Chapter 3 Track Components The track, or Permanent Way, has several parts. It is important to understand how these parts work together to build a safe, stable track. In this chapter, we will talk about these parts and explain why each is important.
C3-1
Formation The formation is the base under the track. It is made of soil that is packed firmly, or compacted in layers.
C3-1.1
Crossfall The bottom of a cutting and the layers of earth in an embankment are sloped away from the centre on double track and from the high side of the formation to the low side on single track. This is called cross-fall. The purpose of cross-fall is to help drain water away from the formation and has a minimum batter angle of 1:30. i.e. for every 300m in length it will drop 1m.
C3-1.2
Embankments Some formations are built up are built up between two high points to reduce grade changes. They are called embankments. Embankments are built of non-cohesive soils (materials which do not stick together and allow water to drain through). Black soils and clays are avoided. Embankments must be well compacted when they are built. They are built in layers of 250 mm. Each layer is compacted with heavy vibrating rollers. Then another layer is added and compacted until the final height is reached.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 38 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Figure 42 – Embankment
C3-1.3
Cuttings Some formations are dug out to reduce grade changes. ie the track has been cut through a hill. They are called cuttings.
Figure 43 – Cutting
C3-1.4
Batters The sides of a formation are called batters. In embankments the batters are usually trimmed to an angle of 1:1.5. In cuttings, the angle of the batters depends on the material they are made of. In the construction of an embankment 1:1.5 means for every 1 metre in height you must increase the width by 1.5 metres.
C3-2
Drainage Drainage systems are extremely important to the stability of the track. Good drains are needed to keep water away from the formation.
C3-2.1
Surface drains 1.
© Rail Corporation Issued June 2012
Top drains or Cut-off drains: are at the top of cuttings. They keep water from washing away the sides of the cutting (erosion) and from running on to the track.
UNCONTROLLED WHEN PRINTED
Page 39 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
2.
Cess drains: are at the bottom of the cuttings. They carry the water away from the formation.
3.
Mitre drains: are used to relieve the build-up of water from Cess and Surface drains and carry the water away from the track. Natural ground slope
Cutoff drain
Cess drain
To waterway
Embankment
Falling grade Cutting
Mitre drains Figure 44 – Surface drains
Figure 45 – Surface drains
Figure 46 – Cess drain
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 40 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
C3-2.2
TMC 202
Sub surface drains Sub drains are placed around platforms etc, where no other kind of drain can be dug. Pipes under the track carry the water away.
Figure 47 – Sumps connected to subsurface drainage
C3-3
Capping layer The capping layer is a well compacted layer of road base material, between the formation and the ballast, and should have a minimum thickness of 150mm. The capping layer stops water entering the formation from above AND stops small particles of soil or fines from entering the ballast from below It is essential that the capping layer is not damaged during track maintenance. Specially made fabrics (geosynthetics) may be used to provide additional strength over weaker formations. These fabrics allow water to drain through but stop mud and dirt coming up from the formation.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 41 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Chapter 4 Track The track structure is the combination of the formation, ballast, drainage, sleepers, fastenings and rails.
Ballast
Rails
Sleeper
Sleeper fastenings Dogspikes Lockspikes
Anchors Sleeper plates
Figure 48 – The Track
C4-1
Ballast Ballast is the material placed between the capping layer and the sleepers. It is a free draining course aggregate. Its purpose is to lock the sleepers in position and to spread the load from the sleepers to the formation.
© Rail Corporation Issued June 2012
1.
There must be at least 270mm for timber (300mm for concrete) of ballast between the sleepers and the formation.
2.
The ballast must be level with the top of the sleepers (this is called “crib”).
3.
There should be at least 400mm of ballast at the end of each sleeper on main line track (this is called the “shoulder”).
4.
The sides of the ballast must slope at an angle of 1:1.5 (this is called the batter angle).
UNCONTROLLED WHEN PRINTED
Page 42 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Ballast slightly above lower centre of some concrete sleepers
Ballast Shoulder
Ballast level with top of timber sleeper
Ballast Crib
Figure 49 - Ballast profile
Ballast shoulder width
Ballast toe 1 1.5
Batter angle
Figure 50 - Ballast profile
C4-2
Sleepers Sleepers or “ties” are a very important part of the track structure. They are used to support the rails and keep them at the correct gauge (ie distance apart) and to transfer the loads from the rails to the ballast.
C4-2.1
Types of sleepers Three types of sleepers are used in Australian railways - timber, concrete and steel. In RailCorp only timber and concrete sleepers are used.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 43 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Anchor
Sleeper plate
Sleeper
Lockspike Dogspike
Figure 51 – Timber dogspiked track
Sleeper
Elastic fastening
Cast-in Shoulder
Insulator
Figure 52 – Concrete sleepered track
C4-2.2
Timber sleepers Timber sleepers are in common use in RailCorp but are being replaced by concrete sleepers. The timber in sleepers is hardwood and includes grey and red ironbark, White and grey box, Grey gum and River red gum species.
Figure 53 – Timber sleepers © Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 44 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
C4-2.3
TMC 202
Timber half sleepers Timber half sleepers are used in some areas of the City Underground and eastern Suburbs railway. They are secured directly to the concrete slab. Rail is attached with sleeper plates and fastenings. Some timber half sleepers in the City Underground have been replaced by polymer concrete half sleepers.
Figure 54 – Timber half sleepers
C4-2.4
Concrete sleepers Concrete sleepers are preferred for use in RailCorp. They are progressively replacing timber sleepers because of: • • • •
Decreasing availability of timber longer life span a more stable track due to greater weight and size price is comparable to timber at the stage where they go under the track (putting them in is more expensive as it is usually fully mechanised)
Cast-in Shoulder
Rail seat sloped at 1 in 20
Figure 55 – Concrete sleepers Concrete sleepers used in RailCorp are monoblock (cast in one piece) prestressed concrete (the reinforcing tendons are stressed before casting the concrete). They have cast in shoulders to hold the resilient fastenings. There are two types of concrete sleeper used in RailCorp: 1.
© Rail Corporation Issued June 2012
Medium duty (also known as low profile). Suitable for use in most applications for axle loads up to 25 tonne. They are approximately the same dimensions as timber sleepers and have been used in some locations mixed with timber sleepers.
UNCONTROLLED WHEN PRINTED
Page 45 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
2.
C4-3
TMC 202
Heavy duty. Used where heavy axle loads operate. They are deeper than timber or medium duty concrete sleepers and track generally needs to be lowered under overhead wiring to fit them in.
Concrete slab track In some locations track is laid directly on a concrete track bed. The rail fastenings are embedded in the slab.
Figure 56 – Concrete slab track
C4-4
Sleeper plates Sleeper plates are attached to timber sleepers to provide a seat for the rail and to keep the rail leaning in towards the track centre at an angle of 1:20. Because the plates have raised shoulders that engage the foot of the rail they also help to maintain the gauge by sharing the lateral load to the lockspikes. There are three types of sleeper plate used in RailCorp on plain track. Double shouldered plates which use lock spikes or lockscrews to hold the plate on the sleeper, dogspikes or dogscrews to hold the rail in the plate (and in the sleeper) and anchors to reduce rail creep. (See Figure 57). Dogspike
Lockspike
Rail seat sloped at 1 in 20
Figure 57 - Double shouldered sleeper plate – used with dogspikes and lockspikes or dogscrews and lockscrews
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 46 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Double shouldered plates which use lock spikes to hold the plate on the sleeper and elastic fastenings (clips) to hold the rail in the plate. (See Figure 58) The clips also reduce rail creep.
Figure 58 - Double shouldered sleeper plate – used with elastic fastenings and lockspikes Double shouldered plates which use screwspikes to hold the plate on the sleeper and elastic fastenings (clips) to hold the rail in the plate. (See Figure 59)
Figure 59 - Double shouldered sleeper plate with screw spikes Concrete sleepers do not use sleeper plates. They are manufactured with cant at the rail seat and have attachments for the fastening systems built into the sleeper. (See Figure 55). Around turnouts some plates are either “cant reducing” or “zero cant”(flat). The rails through turnouts are not sloped inwards at 1 in 20. They stand vertical. This means that the rail either side of the turnout must be gradually changed from 1 in 20 cant to flat. This is done with “cant reducing plates over a number of sleepers.
C4-5
Resilient baseplates In locations where the noise and vibration generated by rail traffic needs to be reduced, resilient baseplates can be used. They are also called vibration isolation fastenings. There are a number of products in use and you may hear them referred to as “Cologne eggs” or “Alternative 1”.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 47 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Figure 60 – Cologne eggs being installed
Figure 61 – Alternative 1 being installed Generally they consist of two baseplates with rubber (or rubber like) material bonded in between. The bottom plate is fastened to the sleeper or directly to a concrete slab. Standard resilient fastenings attach the top plate to the rail.
C4-6
Sleeper fastenings Rails have to be securely fastened to the sleepers to ensure maintenance of correct gauge. To this end we use a variety of sleeper and track plates, spikes, pins, clips, screws and anchors. They have also to be fastened to each other to provide continuity of track.
C4-6.1
Dogspikes Dogspikes are used to hold the foot of the rail in place in timber sleepers. They are hammered through a hole in the sleeper plate into a pre-drilled smaller hole in the sleeper. They hold the rail to “gauge” and prevent the rail from lifting. There are two dogspikes on each rail on each sleeper.
Figure 62 - Dogspike
C4-6.2
Lockspikes They are used to hold sleeper plates and track plates to sleepers and turnout timbers. They come in 2 sizes, the shorter spike (L6) for sleepers (black) and the longer (L1) for turnout timbers (red).
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 48 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Lockspike
Figure 63 – L1 lockspike
C4-6.3
Dogscrew The dogscrew (see Figure 64) is an alternative fastener to the dogspike. The dogscrew consists of a 19mm threaded shank with a 22mm shoulder below the flange. On top of the flange is a 6-lob designed to fit an E24 drive socket. The dogscrew provides greater vertical holding force than the dogspike.
Figure 64 – Dogscrew
C4-6.4
Lockscrew The lockscrew can be used instead of lockspikes. The lockscrew consists of a 16mm threaded shank with a flange and 6-lob head, the same as the dogscrew. There are two types of lockscrew: Small flange – for general use (see Figure 65).
Figure 65 – Small flange lockscrew © Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 49 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Large flange – for use with the automatic magnet pickup machine used by production gangs (see Figure 66). This type cannot be used on rolled Pandrol plates because of the flange interferes with the rolled shoulder and does not sit flush on the plate.
Figure 66 – Large flange lockscrew The lockscrew provides similar cross-sectional strength to the lockspike.
Figure 67 – Dogscrew and lockscrew in track Advantages and disadvantages The benefits of using the dogscrew/lockscrew include: • The dogscrew/lockscrew uses a screwing action for insertion reducing potential injuries from flying objects and swinging of hammers. • The dogscrew has greater vertical holding power and should remain tight for a longer time in comparison to a dogspike. • The dogscrew/lockscrew only requires to be placed upright in the hole before screwing-in where as the standing of a dogspike requires tapping in. • The dogscrew/lockscrew is galvanised for longer life. The disadvantages are: • Sleeper boring hole sizes are different to dog/lockspikes and care will be required when ordering pre-bored sleepers. The dogscrew has a 17mm diameter bored hole (21mm for dogspike) and 14mm diameter hole for the lockscrew (16mm lockspike). • Additional equipment is required to insert and remove these screws.
C4-6.5
Screw spikes They are screwed into place and are used to replace lock spikes on timber sleepers and also in preset holes on concrete bearers a turnout. Special helical washers are used to ensure the screw does not vibrate loose (see Figure 68).
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 50 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Do not insert screw fastenings into existing dogspike or lockspike holes as the sleeper will split.
Figure 68 – Screw spikes and helical spring washer
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 51 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
C4-6.6
TMC 202
Elastic or spring fastenings “e” clip These are elastic steel clips (see Figure 69 to Figure 71).
Standard profile Pandrol E Clip ‘e’ 2003 Low profile Pandrol E Clip‘e’1629 (Blue) FOR USE WITH CONCRETE SLEEPERS AT INSULATED JOINTS Flattened Toe area
Smaller, 16mm dia rod
Low profile Pandrol E Clip‘e’1627 (Red) FOR USE WITH TIMBER SLEEPERS AT INSULATED JOINTS
Figure 69 – different types of ‘e’ clips They are used to hold the flange of the rail in place. They are attached to the sleeper plate and hold the rail flange with a very strong grip. Because they hold so strongly they are also used as anchors. Certain shapes and sizes are used for different purposes. eg timber and concrete sleepers and turnout bearers and around insulated joints to ensure the track circuits are not affected. Plastic insulating pads and spacers are used on concrete sleepers to ensure the track circuits are not affected and to keep the rail in the correct position.
Figure 70 - Low profile clips in use
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 52 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Figure 71 – Standard ‘e’ clip on concrete sleeper Fastclip These are a type of fastening for concrete sleepers that are used to hold the foot of the rail in place and reduce rail creep (See Figure 72 and Figure 73). They are applied laterally and have lugs built into the sleepers to hold the clip. Insulating pads and insulation on the toe of the clip preserve the track circuits.
Figure 72 – Fastclip sleeper assembly
Figure 73 - Fastclip FC 1507 with insulator attached Insulating pads In concrete sleepers a rail seat bearing pad made from high density polyethylene (HDPE) is placed between the rail and the sleeper to cushion the impact of loads. (See Figure 72 and Figure 74) The pad also acts as an insulator between the rail and the sleeper for signal current i.e. to stop the current passing across from rail to rail. © Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 53 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Figure 74 – ‘e’ clip rail seat pad and biscuit Small insulating pads (biscuits) are placed between ‘e’ clip fastenings and the foot of the rail. (See Figure 75). They act as an insulator between the rail and fastenings and also keep the correct gauge. Fastclip systems have an insulator on the toe of the clip. (See Figure 76).
Figure 75 – ‘e’ clip biscuit
C4-6.7
Figure 76 – Fastclip toe insulator
Zero toe load fastenings Zero toe load fastenings are steel caps placed on Pandrol housings. When the Pandrol e-clip is inserted it rests on the top of the cap (See Figure 77 and Figure 78.) No toe load is imposed on the rail. The fastening system maintains gauge and limits vertical movement of the rail It is used on transom topped steel bridges to allow free longitudinal movement of the rail through the fastenings.
Figure 77 – Zero toe load fastenings
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 54 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Figure 78 – Zero toe load fastenings on a guard rail
C4-7
Anchors Rail Anchors are spring steel clips attached to the rail flange (see Figure 79). They lock the rail to the sleepers and stop the rails from moving longitudinally. (along their length). This movement is called rail creep. The rail anchor presently in use is the “Fair” type.
Figure 79 – Fair type rail anchor
C4-8
Rail
C4-8.1
Parts of the rail The various parts of the rail, are known as the “head”, the “web” and the foot (also called the flange). The internal angles formed where head, web and foot meet are known as “fishing angles” or “fishing surfaces”. The names of the different parts of a rail are shown in Figure 80. The surface of the rail head which contacts the wheel treads is referred to as the “running surface” and the side of the head which contacts the wheel flanges is known as the “gauge face”.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 55 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Running Surface Field Corner Region
Gauge Corner Region
Gauge Point (16mm from top)
Head
Gauge Face
Fishing Surfaces
Web
Top of Foot Foot (also known as the flange) Bottom of Foot
Figure 80 – Parts of the rail
C4-8.2
Rail types It Is important that track maintenance staff be able to recognise the various sections of rail used in the RailCorp system. There is a manufacturer's brand on the web of each rail. The rail brand shows: 1.
The name of the manufacturer.
2.
The year the section became Australian Standard.
3.
The section of rail.
4.
The month and year the rail was rolled.
The "heat" number, which gives the batch or ingot from which the rail was rolled is found on the web of the rail on the opposite side of the rail brand. If there is no rail brand, you can identify the rail by its size.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 56 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
60H
BHP
XI\2000 Rail brand
1765736 A Heat Number Head Hardened
60 H
Rail weight
BHP
Manufacturer
XI\2000
Rolling date
Figure 81 – Modern Rail identification
Figure 82 – Old Rail identification
C4-8.3
Rail size If there is no rail brand, you can identify the rail by measuring its height and head and foot widths (See Table 1). Rail height
Foot width
Head width
60 kg/m
170
146
70
53 kg/m
157
146
70
50 kg/m
154
127
70
47 kg/m
141
127
70
80 lb/yd
136.3
127
63.5
Table 1 – Common rail dimensions
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 57 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
C4-9
Rail Joints
C4-9.1
Mechanical joints At a mechanical joint 2 fishplates (bars of steel) are used with fish bolts, spring washers and nuts to mechanically join the rails together. The joint is between two sleepers. The standard variety is the "bar" type with 6 fishbolt holes.
Figure 83 – mechanical joint with fishplates and bolts
C4-9.2
Insulated Joints Insulated Joints are used in track circuited areas where the rails form part of the Signalling System. The joints are placed in the track to prevent the flow of electricity between sections of rail. They divide and isolate the electrical circuit that is used to control the operation of signals, Level Crossing lights and bells, warning lights etc. There are three types: Mechanical insulated Joints - Manually constructed on site. An insulating (nonconducting) material or “fibre” between the rail ends and between the rails, fishplates and fishbolts prevents them from touching or making contact. Mechanical insulated Joints consist of: • A fibre end post in the rail gap to isolate the two rail ends. • Shaped liners to isolate the fishplates from the fishing surfaces of the rail. • Ferrules, or fibre tubes, around the fishbolts to isolate them from the fishplates and the rails. These are not available for 60kg track and must not be used in CWR or concrete track.
Figure 84 – Mechanical Insulated Joint
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 58 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Bonded or Glued Insulated Joints – Specially manufactured and welded into place. Joints are now manufactured with the insulating end post placed at an angle of 15°. This reduced the potential impact on the joint. Glued insulated joints have several advantages over mechanical insulated joints. • The joint is stronger. • Being a rigid joint there is less chance of damage to the insulation through opening and closing of the joint. • The joint can withstand more compression and tension.
Figure 85 – Bonded Insulated Joint
Figure 86 – 15° end post Insulated Plate joints (Benkler joints) – in these joints the fishplate is completely enclosed in insulation and the joint is fastened together with huck bolts. They are only used in turnouts.
Figure 87 – Benkler Joint © Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 59 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
C4-9.3
TMC 202
Junction plates These are normally found in yards and sidings. They are used to join different sections of rail mechanically. They bring both the running surfaces and gauge faces into line. To identify junction plates: Stand with your back to the larger size rail RI = Right hand inner plate. RO =Right hand outer plate. LI =Left hand inner plate. LO =Left hand outer plate. Junction Plates have presented numerous maintenance problems. Often it is difficult to prevent joints becoming ‘foul’ and for this reason “Junction Rails” are now widely used.
Larger Rail size (107) Smaller Rail size (90)
Label – this is “LI” or Left inner
Figure 88 – Junction plate
C4-10
Rail welds Rails are supplied from the manufacturer in 27m lengths. They are welded into longer 110m lengths at RailCorp’s Rail Fabrication Centre at Bathurst using the Flashbutt welding process. When rail is laid in track it is then welded into continuous lengths (Continuous Welded Rail or CWR) using the aluminothermic welding process. This process is also used to replace defective lengths of rail in track and to install bonded insulated joints and junction rails.
C4-10.1
Flashbutt welding In Flash butt welding two rail ends are brought together and supplied with an electrical current. This melts the rail ends, which are then squeezed together under hydraulic pressure, joining the two rails. The resulting excess material around the edge of the weld is sheared off and ground to produce the finished weld. The high heat concentration affects the grain structure of the steel, and results in uneven wear in the vicinity of the weld under traffic. To overcome this, the weld area is heat
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 60 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
treated. This process allows the altered grain structure within the weld to revert to the original grain structure of the rail steel.
C4-10.2
Figure 89 – Rail ends ready for welding
Figure 90 – Flashbutt weld
Figure 91 – Grinding the weld
Figure 92 – Finished weld
Aluminothermic welding In Aluminothermic Welding, parts are joined by utilising liquid metal as filler metal to form a fusion weld with the two rail ends. The rail ends are aligned 25mm apart and enclosed in a two or three part mould. Rail ends are preheated with a flame jet using oxygen and propane gas. After heating the rail ends a crucible containing the aluminothermic powder (the portion which is made up of iron scale to aluminium) is placed above the gap and ignited. The reaction produces heat and melts the metal in the portion. When the reaction is completed the crucible is tapped and the molten metal flows into the mould. The excess material around the edge of the weld is sheared off and ground to produce the finished weld.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 61 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Figure 93 – Preparation for aluminothermic welding
Figure 94 – Weld in progress
Figure 95 – Completed aluminothermic weld
C4-10.3
Junction rails and welds In mainlines, Junction Rails (or Junction Welds) are used to join different size rails together. A junction rail is a forged rail of two different sizes used to connect different sections of rail. A junction weld is a specialised aluminothermic weld used to weld together different sections of rail.
C4-11
Rail lubricators Rail Lubricators are used to help reduce friction between the gauge face of the rails and rolling stock wheels and flanges. If friction is reduced, wear of both these items is reduced which results in cost savings for the owners and the operators of the rail system. Gauge face lubrication is not normally effective in reducing wheel squeal.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 62 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
C4-11.1
TMC 202
Types of lubricators Single pump, single blade lubricators are the preferred type. There are two types of lubricators in use, the P&M (Fessl) and the RTE 25. • All use a pump with a plunger activated by the train wheels and a grease distribution blade to supply the grease to the wheel flange. • The reservoir and pump are on the outside of the high rail of the curve to be lubricated. • The blade is situated on the inside of the high rail. • The RTE 25 has a clamp on assembly whilst the P&M (Fessl) assembly is bolted through the rail.
Figure 96 - P&M lubricator
Figure 97 - RTE 25 pump and reservoir
Figure 98 - RTE 25 Blade assembly
C4-11.2
Type of Grease Rail curve grease has a lithium base with high graphite content.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 63 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Chapter 5 Track layouts Maintaining the connections between tracks is one of the most important parts of track work. All track maintenance workers should be able to recognise any type of track layout and understand its purpose and construction. There are many variations of track layouts. These include turnouts, crossovers, diamonds, single slips, double slips, catchpoints, derails and expansion switches.
C5-1
Turnouts The most common form of connection is the turnout, which is the part of the track that allows trains to move from one track to another. Turnouts can be on either straight or curved track. A turnout is a complete track unit consisting of switches, stockrails, crossings, closure rails, check rails, plates, rail braces, heel blocks, studs, chocks and bearers, and associated fastenings. You will learn more about these components in Chapter 6. Checkrail unit
Crossing
Heel block
Closure rails Studs/switch stops Bearers Stockrails
Rail Brace Plates Switches
Figure 99 - Turnout
C5-1.1
Direction of a Turnout Turnouts are classed as “facing” or “trailing” turnouts, depending on the direction of travel of the train. Facing points are used to turn the rail traffic on to another track.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 64 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
This is determined by whether the train sees the front (or face) of the points when it travels over the turnout (facing), or it sees the points after travelling over the rest of the turnout first (trailing). (See Figure 99 showing a Right hand or facing turnout).
C5-1.2
Hand of a Turnout When you look at a turnout from the points toward the “V” crossing: • A left hand turnout curves towards the left. • A right hand turnout curves towards the right. (See Figure 100).
V Crossing
Turnout curves to LEFT
Turnout curves to RIGHT
Points
Left hand turnout
Right hand turnout
Figure 100 – The “hand” of turnouts
C5-1.3
Turnouts on curved track When turnouts are constructed on curved track, they are known as either “Similar Flexure” or “Contrary Flexure” turnouts.
C5-1.3.1
Similar flexure turnouts: Similar flexure turnouts follow the same direction as the main line curve. There are two types of Similar Flexure Turnouts: • Similar flexure turnout on the inside. This is when the crossing is on the inner rail of the main line and the turnout curve has a smaller radius than the main line.
Main
Turnout road
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 65 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
• Similar flexure turnout on the outside. This is when the crossing is on the outer rail of the main line and the turnout curve has a larger radius than the main line. Turnout road Main
C5-1.3.2
Contrary Flexure Turnouts Contrary flexure turnouts curve in the opposite direction to the main line curve. Turnout road
Main
C5-1.4
Turnout type There are two types of turnout used in the RailCorp. 1.
Conventional
2.
Tangential
The distinction between the two types is based on geometry and component technology. Conventional turnouts Standard conventional turnouts are defined by a combination of the switch length and heel angle, and the crossing rate. Conventional turnouts may be left or right hand. Standard conventional turnouts are designed with the main line track straight. Conventional turnouts were designed in RailCorp and, depending on when they were installed, all have the same types of components. Tangential turnouts Tangential turnouts are defined by the radius of the turnout. Tangential turnout designs have a standard configuration (footprint) onto which each turnout manufacturer has placed their own design. This means that components vary in tangential turnouts.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 66 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Tangential turnouts have been designed to closely align with existing designs so that the adjoining track, overhead wiring and signalling will only need minimal adjustment. They offer higher speed than conventional turnouts and are the standard type now being installed in RailCorp. There are still many conventional turnouts in RailCorp track.
C5-2
Crossover Crossovers connect two tracks. It is made up from two turnouts on adjacent tracks, generally connected by a short section of plain track. They can be left hand or right hand. They are also known as either facing or trailing. This is determined by whether the train sees the front (or face) of the points when it travels over the turnout (facing) , or it sees the points after travelling over the rest of the turnout first (trailing). (See Figure 101 showing a Right hand or facing crossover). Direction of travel
Direction of travel Figure 101 – Crossover
C5-3
Diamond A diamond is formed when a crossover passes through a third track.
Figure 102 - Diamond
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 67 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
V Crossing
K Crossing K Crossing
V Crossing
Figure 103 - Diamond
C5-4
Slips Slips are created when diamonds are modified to allow connection of the third running line to the crossover. Slips may be either: • Single slip where this connection is made for traffic in one direction only. Single slips have 2 sets of switches. (See Figure 104). • Double slip which allows this connection to be made for traffic in two directions. Double slips have four sets of switches. (See Figure 105).
Possible paths
Figure 104 – Example of a Single slip
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 68 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Possible paths
Figure 105 – Example of a Double slip
C5-5
Catch points Catch points are used to keep running lines clear of unwanted trains. They are a single switch that can be opened to allow vehicle wheels to derail. They are often found where sidings are connected to running lines so that a train will derail at the catchpoint before it leaves the siding and fouls the main line. They are provided with a “throw-off rail” and a “derail block” to guide the rail vehicle away from the running line. At some locations where there is not sufficient area adjacent to the track for trains to run off safely, a guard rail is installed in the "four foot" to keep the derailed train close to the track. The catch points are located to provide a minimum of 450mm between the side of the vehicle on the running line and the vehicle being derailed on the catch point.
Derail block Throw off rail
Catchpoint
Figure 106 – Catchpoints with throw-off rail
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 69 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Figure 107 – Catchpoints with guard rail
C5-6
Derailer A Derailer is used for the same purpose as a set of catchpoints.
Derailer Crowder
Figure 108 – Derailer
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 70 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
C5-7
TMC 202
Expansion Switches Expansion Switches are used as a level of control for rail stresses when tracks are attached to sub structures (eg steel underbridges) that are also subject to temperature related expansion & contraction. Tangential expansion switches are designed to operate in a range of +/- 150mm.
Figure 109 – Hawkesbury River Bridge Tangential Expansion switch
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 71 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Chapter 6 Turnout Components A turnout consists of four sections: Points, Crossing, Checkrails and Closure Rails.
Points
Closure Rails
Check Rail
Check Rail
Crossing
Figure 110 – The parts of a turnout
C6-1
Points A set of points is a fully assembled pair of switches and stockrail units with chairs, switch stops, rail brace plates and the required rodding attached to correctly operate the switches. Points may be interlocked (that is connected by rodding to points machines and operated remotely as part of the signalling system), or non-interlocked in which case they are operated manually by levers placed next to the points. Heel block Studs/switch stops
Bearers Stockrails
Rail Brace Plates Switches Signal Interlocking
Figure 111 - Points
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 72 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
C6-1.1
TMC 202
Switch A standard switch consists of a section of rail or rail steel that has been set and machined to a design shape, then drilled to detail to accommodate gauge rod brackets and heel blocks. When it is set against the stockrail, it directs the wheel flanges and causes the change of direction of traffic.
C6-1.1.1
Left or right hand switches Due to the machined shape of the switches, they are classified as being either right or left hand. To identify switches, you must stand at the points looking back towards the “V” crossing. The switch on the right is the right hand switch; the switch on the left is the left hand switch. (See Figure 112). V Crossing
Left hand switch
Points
Right hand switch
Figure 112 – Hand of a switch
C6-1.1.2
Switch types Switches are produced in various sizes and types. They may be either: • Conventional • Undercut, OR • Asymmetric 1.
Conventional switch Conventional switches are machined from rails and tapered down from a full rail at the heel, to a thin point that fits closely against the stock rail. They are only in use with 47kg and 53kg rail and are not used when turnouts are renewed. In conventional switches: o There is no machining on the stockrail. o The switch rail is machined and vertically set to override the foot of the stockrail.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 73 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Conventional switches may be: Standard Standard switches: o have a narrow machined point of 3mm, o have a straight stockrail.
Figure 113 - Standard Conventional switch Heavy Duty Heavy Duty switches: o o o o
have a machined point 19mm thick, have a joggled stockrail, are used in 53kg turnouts ONLY, are only used where the points are in the facing direction and are subject to heavy wear.
Joggle
Figure 114 - Heavy duty switch tip and joggled stockrail © Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 74 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Housed If heavy duty switches and joggled stockrails are used on both rails, a switch “housing” is provided on one of the switches. The housing is a specially machined component with a hardened checking face. It acts as a checkrail to control the position of the wheels when they pass the joggle and switch points.
Housing Heavy duty switch
Joggle
Figure 115 - Heavy duty switches with housed points 2.
Undercut Switches Switches for use with 50kg and 60kg rail have the stockrail undercut by machining to allow the switch to move partially under the head of the stockrail. The foot of both the switch and stockrail sit at the same level.
Figure 116 – Undercut switch 3.
Asymmetric switch Switches used with 60kg tangential designs are called asymmetric. They are not machined from rail. They have a thick web and are shallower than conventional and undercut switches. Asymmetric switches ride on a raised slide table.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 75 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
The switch rail material is forged at the heel to form the shape of the rail section so that it can be welded to the closure rail. A section is cut out from the rail foot at the heel to reduce the force required to operate the points. It is easier to maintain adequate heel flangeway opening for a given toe opening compared with conventional and undercut switches because the asymmetric section is far stiffer then the standard section in horizontal bending. The asymmetric shape is more stable under the wheel load.
Figure 117 - Asymmetric switch tip and rollers
C6-1.1.3
Heeled Switches Heeled switches are switches that pivot from a gapped joint between the switch rail and the adjoining closure rail. The heel block and fishplate at this joint are designed to allow the movement. The switch length is the total length of the switch rail.
C6-1.1.4
Flexible Switches Flexible switches are machined from longer rails and fixed towards the end of this rail with blocks to the adjacent stockrail. A section of the switch rail foot is removed close to the securing (heel) blocks and the switch is designed to flex over its length.
Figure 118 - Flexible switches © Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 76 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
C6-1.2
TMC 202
Stockrails The rail against which the switch fits is known as the stock rail. It provides support for the closed switch and become the running rail when the switch is open. In a turnout there are two stock rails. These are identified as being left or right handed in the same way as switches and turnouts are identified. Stockrails can be either standard full rail sections (for use with conventional switches) or machine undercut (for use with undercut and asymmetric switches). They are curved, set and/or joggled and drilled during manufacture to suit the chairs and switch stops. The stockrail on the turnout side of the turnout is bent or ‘set’ in front of the switch to allow the gauge lines of the standard switch.
C6-1.2.1
Front of stockrail The distance from the point of the switch to the nearest end of the stockrail is called the “front” of the turnout.
C6-1.2.2
Joggled Stockrail To compensate for the extra thickness in the nose of a heavy duty switch, the stockrail is “joggled” by approx 20mm. The setting of the joggle allows for the correct alignment of the switch and also prevents the wheel flange striking the nose of the switch.
C6-1.2.3
Housing If heavy duty switches and joggled stockrails are used on both rails, a switch “housing” is provided as the gauge will be approx 20mm wide. The housing is made from manganese steel rail. It acts as a checkrail to control the position of the wheels when they pass the joggle and switch points. The provision of the housing enables the joggled stockrail and heavy duty switches to be used on almost any type of layout.
C6-1.3
Heel block Heel Blocks are cast wedges that fit in the fishing surfaces of the rail at the rear end between the stockrail and switch. In heeled switches, the heel block and associated fishplates and bolts are designed to allow a movement of the switch blade at this point similar to a hinge. The heel blocks allow enough movement in the ‘heel Joint’ to allow the switches to be reversed from side to side. (See Figure 119). In flexible switches there are two heel blocks attached to the end of the switch and the adjacent stockrail and closure rail. They are fabricated blocks that rigidly fix the switch rail to the adjacent rail in the correct geometric position. (See Figure 120). It ensures that longitudinal thermal expansion and contraction of the switchblade is confined to the unrestrained portion of the switchblade that lies ahead of the anti-creep device.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 77 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Heel centres
Figure 119 - Heel block for heeled switches
Figure 120 - Heel block for flexible switches
C6-1.3.1
Heel centre The heel centre is the distance between centre of the stockrail and the centre of the switch. The heel centre is located at a defined distance from the nose of the switch. At the heel centre the distance between the centre of the switch and the centre of the stockrail is always 159mm. The heel centre is measured from the gauge face of the switch to the gauge face of the stockrail.
C6-1.4
Anti-creep device In some tangential turnout designs there are NO heel blocks. The switch stops and the fastening systems hold the stockrail and the switch in the correct position. In these designs an anti-creep device is fitted between each switchblade and its matching stockrail near the heel end of the switch rail. This is designed to prevent differential
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 78 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
longitudinal movement of the switchblades relative to their stockrails caused through rail creep.
Figure 121 – Anti-creep device
C6-1.5
Cant reducing plates Cant reducing plates are used on the approaches at either end of the turnout. They provide a gradual reduction of rail inclination from 1:20 on the open track to the flat track plates used through turnouts.
Figure 122 - Cant reducing plates
C6-1.6
Chairs A chair is a flat plate that is attached with a bolt through the web of the stockrail. Chairs are used to support the points assembly on the bearers. The type of chair is identified by lettering on the end of the plate eg. SR, A, B, C, D. With undercut switch designs used with 60kg and 50kg switches, the plates are flat under the switch/stockrail.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 79 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Asymmetric switches use a different type of fastening and support system. They do not use chairs or rail brace plates. With the 53kg and 47kg switch designs using standard or heavy duty switches, the plates under the first 3 bearers from the point of the switch have a raised table to support the switch. 1.
SR Chairs Stockrail or S/R chairs are used on the two bearers immediately in front of the switches. Their purpose is to provide additional support for the stockrail.
Figure 123 - “SR” chair 2.
A, B, C and D chairs When a switch is manufactured, it is bent upwards, or vertically set, to allow more steel to be retained in the foot of the switch while still allowing it to close up correctly. This vertical set equals 9 mm at the point of the switch. Correspondingly, the chair that is placed on the timber immediately under the point of the switch is provided with a 9 mm raised table upon which the switch slides. This chair is called the ‘A’ chair.
Figure 124 - A, B, and C chairs under a standard switch The next chair back is called the ‘B’ chair. The ‘B’ chair has a table 6 mm tall. ‘C’ chairs are next with a 3mm table. ‘D’ chairs follow and are used as far back as the heel block. ‘D’ chairs have no raised table. The base is flat.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 80 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Figure 125 - “D” chair
C6-1.7
Rail brace plates Rail brace plates are used under the switch assembly. A cast rail brace is attached to the switch assembly and then bolted to the stockrail. The rail brace contacts the underside of the head and the top of the foot of the stockrail. It is used for stockrail support and to maintain the gauge. They may be used in place of “A” and “B” chairs or in places “A”, “B”, “C” and “D” chairs on some newer turnouts. The plates are identified by a number stamped on the end of the plate.
Figure 126 - Rail brace and plate
C6-1.8
Split plates Split plates are another type of fastening system used to hold the rails in place.
Figure 127 - Double shouldered flat plates and split plates
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 81 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
C6-1.9
TMC 202
Switch plates and fastenings in tangential turnouts Each turnout manufacture has there own design of plates and fastenings for switches and stockrails. They support the stock rail resiliently without interfering with switch rail movement or maintainability. TKL Rail uses the “Schwihag System” of inner stockrail bracing clips and special elevated side tables. PRE uses the PVT Clip – inner stock rail fastening. VAE uses their own patented switch fastening system
Figure 128 - Asymmetric switch sitting on raised plates
C6-1.10
Switch stops (switch studs) Switch stops are made from castings, rolled angle section or extended bolts. They are bolted to the web of the stockrail through the chairs or rail brace plates. When the switch is in the closed position, they make contact with its web, providing support for the switch as it is subjected to the thrust of wheel flanges. When replacing switch stops, make sure you use the correct size. The stops get longer towards the heel. • If the stops are too long, they will not allow the switch to close. • If the stops are too short, they will not support the switch.
Figure 129 – Switch stops
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 82 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
C6-1.11
TMC 202
Switch rollers Special rollers, which are either built into the bed plates or clamped to the stockrail and sit under the switch, are sometimes used to assist flexible switches in opening and closing.
Figure 130 – Switch roller systems from different manufacturers
C6-1.12
In-bearers Hollow steel turnout bearers that are installed instead of the first two bearers at the switches. Points detection equipment and interlocking can be installed inside the inbearer. This means that the bays between the bearers are clear of obstructions and can be tamped.
Figure 131 – Steel In-bearers
Figure 132 – Steel In-bearers in track with signalling gear installed © Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 83 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
C6-2
TMC 202
Closure rails The closure rails form the remaining portion of the turnout. These rails are crowed to their correct radius before installation and are fastened on flat double shouldered track plates. The closure rails on the turnout road must be laid with the correct offset from the mainline to ensure the correct radius from the heel block to the “V” crossing.
C6-3
Crossing The next section of the turnout is the crossing. It is known as a “V” crossing. Its purpose is to provide a path for the wheel flange to travel across the point where two running rails cross over.
Figure 133 – V Crossing
C6-3.1
Theoretical point and practical point. Theoretical point The point where the gauge faces of the running line and the turnout rail would intersect is known as the theoretical point. The theoretical point is the start point for all turnout and crossing dimensions. It is usually punched marked on the wing rails over the centre bolt. If, however, the punch marks are not visible, you can find the theoretical point of a straight crossing as follows:
© Rail Corporation Issued June 2012
1.
Stretch a string line along the gauge faces from the front leg to back leg of the crossing. Hold the string 16mm below the running surface.
2.
Stretch a second string line along the opposite gauge faces, once again from the front to back leg and hold the string at 16mm below the running surface.
3.
Mark the point at which the string lines cross over or intersect. This is the theoretical point of intersection.
UNCONTROLLED WHEN PRINTED
Page 84 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Theoretical Point of intersection
Practical Point
Figure 134 – Theoretical and Practical points Practical point The end or “nose” of the point rail is known as the practical point of the crossing. The gauge and the checkrail effectiveness are measured from the practical point.
C6-3.2
Crossing rate The crossing rate is a measure of the angle made by the rail gauge faces at the theoretical point. The larger the crossing rate, the smaller the angle, the faster the speed through the crossing. The identifying catalogue number of the crossing is stamped on the top surface of the wing rail end along with the manufacturer’s identification. In newer crossings the information is engraved on a label attached to the web of the crossing showing details of geometry, date of manufacture, material used in the crossing and work order number (See Figure 135). Rail size
Crossing rate
Manufacture date
Catalogue No. Crossing material
Figure 135 – Crossing identification label The catalogue number gives details concerning the rate of the crossing, whether it-has a left or right hand point rail and whether it has the front, back or both legs curved.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 85 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
To determine the crossing angle if no identification is available: 1.
Locate the theoretical point by stringlining the gauge faces of the crossing.
2.
Mark this point.
3.
Locate a point where the gauge faces of the point rail and wing rail separate to a distance of exactly 100mm.
4.
Accurately measure the distance between this point and the theoretical point.
5.
The crossing rate is equal to this measurement, divided by 100. e.g.
The distance from the theoretical point to the point where the gauge faces separate 100mm is equal to 1050 mm. Therefore, crossing rate = 1050/100 = 10.5. crossing rate = 1:10.5. Wing rail Theoretical intersection of crossing
Point rail 100mm
1
100mm
10.5
Housed rail 1050mm Wing rail
Figure 136 – Crossing rate
C6-3.3
Type of Crossing There are 2 types of V crossings • Fixed crossings • Switchable crossings
C6-3.4
Fixed crossings These crossings have a wheel flange gap in both rails. Wheel transfer of fixed crossings depend on matching wheel and rail profiles. Fixed crossings are used in conjunction with check (guide) rails to provide lateral guidance in the crossing area. Fixed crossings may be: • • • •
© Rail Corporation Issued June 2012
Fabricated crossings. Rail Bound Manganese crossings. Compound crossings Fully cast crossings
UNCONTROLLED WHEN PRINTED
Page 86 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
C6-3.5
TMC 202
Fabricated crossings The component parts of the crossing are the wing rails, the point rails and the housed rail. A fabricated “V” crossing comprises a Vee (made up from the point rail and the housed rail) and 2 wing rails fabricated from sections of rail that have been machined and fitted together with chocks and high tensile fastenings. Certain chocks will be set with epoxy paste.
C6-3.5.1
Hand of fabricated crossings. All fabricated crossings are also referred to as being either right or left hand. To identify a crossing, stand at the back of the crossing and look toward the practical point. A right hand crossing is one where the point rail is on the right, a left hand crossing where the point rail is on the left.
Housed rail
Chocks
Point rail
A left hand crossing has the point rail on the left hand running rail of the turnout (the rail that connects to the left hand switch).
Wing rails
As a general rule, the point rail should always be laid for the main line or the line carrying the most traffic. This is due to the point rail being more durable than the housed rail.
Left hand crossing Figure 137 - Fabricated crossing
C6-3.6
Compound Crossing A compound crossing is a crossing V point that is manufactured from a single cast nose that is welded to head hardened rails to complete the V. This replaces the point/housed rails in a fabricated crossing. Compound crossings may be manufactured from manganese steel, chrome vanadium alloys or other materials.
C6-3.6.1
Compound Manganese Crossing A Compound Manganese crossing is a compound crossing V point that is manufactured from a cast manganese nose which is explosively hardened and flashbutt welded to head hardened rails to complete the V.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 87 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
C6-3.6.2
TMC 202
Chrome Vanadium crossing A Compound Chrome vanadium crossing is a compound crossing V point that is manufactured from a cast chrome vanadium steel nose which is welded to head hardened rails to complete the V.
Figure 138 - Chrome vanadium crossing
C6-3.6.3
Identifying crossings Compound crossings are identified by the following code on the crossing identification label (See Figure 135). MN - Compound Manganese (MANG also used in some). CV - Chrome Vanadium (CHV also used in some). If there is no plate on the crossing, or the plate is unreadable, the type of material can be established using the following guidelines.
© Rail Corporation Issued June 2012
1.
If the nose is manufactured from two standard rail sections, machined and fitted together it is a fabricated crossing (normal rail steel).
2.
If the nose is manufactured in one piece it will be either Compound Manganese or Chrome Vanadium.
UNCONTROLLED WHEN PRINTED
Page 88 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
3.
If the one piece nose was installed in track before 1999 it will usually be Chrome Vanadium.
4.
If the one piece nose was installed in track since 2000 it will usually be Compound Manganese. All current “V” crossing noses are manufactured from Compound Manganese.
5.
Chrome Vanadium crossings have the crossing chocks welded to the crossing nose.
6.
Manganese crossings have the crossing chocks glued or cast to the crossing nose.
7.
Manganese crossings can also be identified in the field by the stainless steel insert, 8mm to 15mm wide, that can be found where the crossing head width is about 84mm. Once paint/ dirt is removed the insert will be shiny.
8.
The manganese noses are non magnetic while those made from rail steel and chrome vanadium are magnetic. That is a magnet will not stick to manganese crossing noses but will stick to other types.
Chocks welded to crossing insert
Chocks not attached
Figure 139 - Chrome Vanadium crossing
Manganese Crossing Nose
Figure 140 - Manganese crossing
84 mm approx.
Stainless Steel Insert
Figure 141 - Stainless Steel Insert with manganese crossing
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 89 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
C6-3.6.4
TMC 202
Rail Bound Manganese Crossings Rail Bound Manganese Crossings are crossings with the actual crossing area made from manganese steel casting and surrounded by specially machined and set wings manufactured from normal rail.
Figure 142 - Rail bound manganese crossing
C6-3.6.5
Fully cast (monobloc) crossing A one piece solid cast steel crossing with the four legs joined to standard rail sections through a welding process or by bolts and plates. With monobloc crossings the whole crossing is made from manganese including the wing section and all joining material. The monobloc section is flashbutt welded to 60kg/m rail so the crossing can be welded into track in the same way as conventional crossings.
Leg ends made from 60kg/m rail Solid monbloc manganese casting
Leg ends made from 60kg/m rail
Figure 143 - Monobloc crossing © Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 90 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
The monobloc crossing has features that are different to conventional crossing designs. Like other manganese components they cannot be ultrasonically tested.
Figure 144 - Monobloc crossing
C6-3.7
Switchable crossings These crossings close the gap in one track that is being made active for traffic allowing a continuous surface for the wheel to run through the crossing. Wheel transfer in switchable crossings is without any impact for any wheel profile. Switchable crossings have no flange gap in the active track and thus do not require checkrails. They can have either Swing Nose or Spring Wing.
C6-3.7.1
Swing Nose Crossing Swing Nose Crossings are fabricated crossings, used in medium and high speed turnouts, where the point of the crossing can be moved horizontally with the use of motor driven signalling equipment. Swing nose crossings have no checkrails.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 91 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Figure 145 - Swing nose crossings
C6-3.7.2
Spring Wing crossing A switchable V crossing with both a fixed and spring wing leg. The spring wing effectively eliminates the flange way gap when using the main line thus reducing the wheel generated impact in the crossing. The wheel flange forces the spring wing open when taking the siding road.
C6-4
Checkrail unit The checkrail units are opposite the “V” crossing. The purpose of the checkrails is to control the position and direction of the vehicle wheels as they pass through the flangeways of the crossing. (See Figure 146). The unit consists of a length of rail (called the checkrail) with a flared bevel machined on each end, hardened on the checking face, bolted through chocks/shims to a closure rail (called the checkrail carrier). The centre of the checkrail should be opposite the theoretical point of the “V” crossing. Straight check rails are chamfered. This means that the same size chock can be used all the way through and there is no need for shims. (See Figure 147). On some turnouts (eg tangentials) the checkrail is higher than the checkrail carrier. They are made from special guard rail section (UIC 33) and bolted to special elevated guard rail chairs. This is called a raised checkrail. (See Figure 148). The centre of the checkrail is usually opposite the theoretical point of the crossing. Due to the construction of “V” crossings, there is a gap between the practical point and the throat across which there is no rail to guide the wheel. When a wheel follows the
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 92 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
outer rail of the turnout the tendency is for it to travel outwards when it reaches the gap. If this occurs, the wheel flange could travel on the wrong side of the crossing and derail. This is prevented by the checkrail that engages the back of the opposite wheel and guides the flange onto the correct side of the crossing point. This action takes place each time a wheel moves in a facing direction through a crossing and the whole safety of the movement depends on the checkrail. Consequently, the maintenance of the correct position and rigid fastening of the checkrail is of particular importance. Some Checkrail flangeways are adjusted by using spacer shims with the chocks.
Figure 146 - Checkrails at the “v” crossing
Figure 147 – Checkrail machine chamfered from straight rail
Figure 148 – Raised checkrail © Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 93 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
C6-4.1
TMC 202
Chocks A chock is an iron casting used mainly with check rails and crossings to support rail components at a fixed distance apart. Raised lettering and numbers on the chock identify its application.
Figure 149 - A checkrail chock
C6-4.2
CR Chairs CR Chairs are used to attach the checkrail to the checkrail carrier and provide support for the checkrail. The brace comes in from the ‘4 foot’ side of the checkrail and is bolted through to the checkrail carrier. These chairs are an old design and are being phased out with the use of PCR plates (double pandrol plates that fit under checkrail units).
C6-5
Operation of points
C6-5.1
Interlocked points All main line switches are connected to the signalling system (interlocks) and are, generally operated by motor driven point machines. They are installed and maintained by the signals discipline.
Figure 150 – Signals interlocking at points
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 94 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
C6-5.2
TMC 202
Manual points Most yard and siding turnouts are not connected to the signalling system and are operated by manual point levers. They are installed and maintained by the civil discipline. The different types of manual levers include: 9.
Ball and Throw over levers.
10.
Thornley levers.
Ball and Throw over levers in most cases have been replaced with Thornley Levers.
Figure 151 - Ball lever
Figure 152 - Throw over lever
Figure 153 - Thornley lever
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 95 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Figure 154 – National Trackwork lever
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 96 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Chapter 7 Tools and plant Work on the track infrastructure is carried out using a variety of tools. These range from small hand tools to large, complex on-track machines. Some tools are common and are available from any hardware store. There are, however, some special tools that are designed and manufactured for railway application. This chapter describes some of these tools and plant items.
C7-1
Manual tools Claw wedge The claw wedge or "pigs foot" is designed to remove dog spikes from the sleepers. It looks like the “claw” on a hammer, and is wedged under the head of the dogspike and hit with a spiking hammer.
Figure 155 – Claw wedge
Figure 156 – Claw bar
Claw bar A claw bar is like a claw wedge with a long handle. By levering with the handle you can lift dogspikes out of the sleeper. Sleeper tongs Sleeper tongs are used to move or lift sleepers manually. They have two handles so that one man can stand either side of the sleeper and hold a handle each.
Figure 157 – Sleeper tongs
© Rail Corporation Issued June 2012
Figure 158 – Rail tongs
UNCONTROLLED WHEN PRINTED
Page 97 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Rail tongs Rail tongs clamp around rail and are used to lift and move rail. Like sleeper tongs, they have two handles allowing two men to hold a set of tongs. Spiking hammer A spiking hammer is a “sledge” hammer with one end (or both ends) forged into a point. This end is used to drive in dogspikes and lockspikes without damaging the rail.
Figure 159 – Spiking hammer Rail turning bar A rail turning bar is a long bar with a specially shaped head. The indents in the head are used to grip either the head or foot of a rail so that the rail can be turned over.
Figure 160 Rail turning bar
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 98 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Podger A podger is a round wedge. It is driven inserted through a fishbolt hole in a fishplate into the corresponding hole in the rail. By driving the podger with a hammer, the holes can be lined up so that a fishbolt will fit.
Figure 161 – Podger
Figure 162 – Draw wedge
Draw wedge A Draw wedge is used to make small adjustments when lining up rail ends. Panpuller and Pansetter These tools are used to remove or install Pandrol e-clips on sleepers. Use them instead of a spiking hammer. Panpuller head
Pansetter head Figure 163 – Panpuller
© Rail Corporation Issued June 2012
Figure 164 – Pansetter
UNCONTROLLED WHEN PRINTED
Page 99 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Welder’s Hot Set A Welder’s Hot Set is a chisel attached to a long handle. It is used by welders to cut hot weld material away from the rail head immediately after welding
Figure 165 - Welder’s Hot Set Beater pick A beater pick is a pick with one end forged to a wide, flat pad (or beater). The beater is used to pack ballast under sleepers.
C7-2
Small plant
Figure 166 – Fastclip applicator
Figure 168 – Pin puller
© Rail Corporation Issued June 2012
Figure 167 – Pandrol clipper
Figure 169 – Dogscrew inserter
UNCONTROLLED WHEN PRINTED
Page 100 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Figure 170 – Air hammer
Figure 171 – Tamper
Figure 172 – Hydraulic jack
Figure 173 – Impact wrenches
Figure 174 – Rail saws
Figure 175 – Rail drills © Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 101 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Figure 176 – Sleeper borer
Figure 177 – Fastclip applicator
Figure 178 – Rail tensors
Figure 179 – Weld shears
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 102 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
C7-3
TMC 202
Off track plant
Figure 180 – Hi-rail backhoe
Figure 181 – Tamping attachment for Hirail backhoe
Figure 182 – Rail lifting attachment for Hi-rail backhoe
Figure 183 – 360 Crane
Figure 184 – Sleeper lift attachment for 360 Crane
© Rail Corporation Issued June 2012
Figure 185 – Tamping attachment for 360 Crane
UNCONTROLLED WHEN PRINTED
Page 103 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Figure 186 – Spot Tamper
C7-4
Figure 187 – Pettibone crane
Resurfacing machines
Figure 188 – Unimat 09-32/4S Tamper/liner
Figure 189 – Unimat 09-32/4S in action
Figure 190 – Cat 09-16 tamper
© Rail Corporation Issued June 2012
Figure 191 Cat 07-275 Turnout tamper
UNCONTROLLED WHEN PRINTED
Page 104 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Figure 192 – SSP302 High Speed Ballast Regulator
Figure 194 – USP3000C Ballast Regulator
C7-5
Figure 193 - SSP110 High Speed Ballast Regulator
Figure 195 – Ballast stabiliser
Turnout transporter and layer
Figure 196 – Desec Track layer transporting and lifting turnouts
Figure 197 – Desec Track layer laying new turnout
© Rail Corporation Issued June 2012
Figure 198 – Transporting a turnout
UNCONTROLLED WHEN PRINTED
Page 105 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
C7-6
TMC 202
Ballast cleaners
Figure 199 – RM 900 Ballast cleaner
Figure 200 – RM 900 in action
Figure 201 – RM 74 in action
Figure 202 – Spoil wagons and conveyor for RM 900
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 106 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
C7-7
TMC 202
Track Laying Machine (TLM)
Figure 203 – TLM laying concrete sleepers
Figure 204 – Sleeper wagons
C7-8
Figure 205 – Gantry Crane (Transporter)
Rerailing plant
Figure 206 – Rail laying train
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 107 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Figure 207 – Old method of loading rail
Figure 208 – Rail laying train
Figure 209 – Rail manipulator
C7-9
Rail grinder
Figure 210 – Rail grinder
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 108 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Chapter 8 Track Geometry The Permanent Way is designed using standard geometric shapes. Circular curves and straight lines form the basis of the track with transitions forming a gradual joining of the two. The following terms and definitions are essential knowledge to help understand the basics of track geometry.
C8-1
Simple geometry Mid Ordinate Versine
Chord
Radius
Diameter
Arc
Tangent point Tangent Figure 211 – Geometry terms
C8-1.1
Circle Is a shape, formed by a continuous line that is always the same distance from the centre point.
C8-1.2
Tangent Is a straight line that touches a circle at one point (in rail terms, tangent track is straight track).
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 109 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
C8-1.3
TMC 202
Circumference Is the continuous line that forms a circle.
C8-1.4
Arc Is any part of a circumference.
C8-1.5
Diameter Is a straight line drawn from one point to another point on the circumference (through the centre).
C8-1.6
Chord Is a straight line drawn from one point to another point on the circumference (not through the centre).
C8-1.7
Radius Any straight line drawn from the centre of a circle to a point on its circumference. The plural of radius is radii. The radius of a circle is a constant length.
C8-1.8
Middle Ordinate The distance measured at right angles from the centre of a chord to the circumference.
C8-1.9
Versine Distance measured at right angles from any given point on the chord to the circumference.
C8-1.10
Tangent Point (TP) Is the point where a straight line touches a circle. In railway terms, the tangent point is the point where the straight meets the curve.
C8-1.11
Transition Point (TRS) Is the point at which the transition meets the circular curve.
C8-1.12
Compound Tangent Point (CTP) Is the point where two curves of different radii meet in a non-transitioned compound curve.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 110 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
C8-1.13
TMC 202
Compound Transition (CTRS) Are used to connect transitioned compound curves and reverse curves. The CTRS is the point where the transition begins to join one radius curve to another.
C8-2
Curves Curves are provided in a railway route to change direction. This allows the line to: • follow the natural contour of the country, reducing construction costs by avoiding heavy earthworks, etc., and • be lengthened to obtain grades at locations where a grade on a straight line between two points would be excessively steep for traffic. In general practice, curves are always located with the greatest possible radius consistent with economical layout. In heavy and mountainous country, relatively sharp curves occur and are responsible for reduction of the maximum permissible speed for the line. Curved tracks introduce problems not associated with straight tracks caused by the action and effects of vehicles entering and travelling around curves. When a vehicle moves in a straight line there is no change of direction; but when it enters a curve it changes direction. How quickly it changes direction depends on speed and curve radius. The faster the change the greater the forces exerted. Large accelerations and forces are undesirable for passenger comfort and, ultimately, safe operation of trains. Once a vehicle has fully entered a circular curve the rate of change of direction becomes constant, but as it moves out of the curve back into a straight, or into another curve a similar change occurs, which produces the same conditions of acceleration and force. In order to remove these effects, a transition curve is used (See Section C8-2.4). This curve has the effect of gradually increasing the amount of displacement in a given length. The displacement takes place at a slower rate and, consequently, the forces exerted on the vehicle are more uniformly and evenly applied, and reach their maximum as the vehicle reaches the commencement of the circular curve. When a vehicle travels on a straight track, its weight is uniformly distributed through the wheels to both rails, but when it enters a curve this distribution is altered and the load on the outer rail is increased. The amount of increase depends on the speed of the vehicle and the radius of the curve. It is possible with excessive speed to reach a condition where the whole of the weight is carried on the outer rail, and in such an extreme case, overturning may occur. To counteract the increased loading on the outer rail, the outer rail is raised above the level of the inner rail. This is known as “superelevation” (or cant) (See Section C8-2.5) and its effect is to permit higher speeds on curves, due to the increased stability against overturning, and to improve the riding of vehicles entering and running on curves. As superelevation is only necessary on curved tracks, it is difficult to suitably arrange its application at the tangent points of circular curves where the change of direction and increased loading of the outer rail both occur at the one time and give rise to rough riding and difficulty in maintaining correct alignment. This condition is improved by using transition curves.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 111 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
When a curved track is laid accurately to a position set out by a surveyor, it represents an almost perfect circular curve of given radius; but under traffic conditions distortion occurs and while the general average radius remains, it becomes a series of “flats” and “sharps”. In such a curve, a “flat” is a portion of the curve where the radius was greater than the given radius, and a “sharp” is a portion of smaller radius. The two types of curves found in tracks are described as “circular” and “transition” a circular curve being a curve of constant radius and a transition curve, a curve of varying radius. Conventions When describing the rails of tracks on curves, the rail of greater radius is called the “Outer Rail” and the rail of smaller radius is called the “Inner Rail”. The length of radius is given in metres and with any increase or decrease of this length, the curve is referred to as “flatter” or “sharper” respectively. It is usual to speak of a curve by its radius. That is, a 400metre curve is a curve having a radius of 400 metres.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 112 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Tangent TP Tangent Point Transition
TRS Transition Point Circular Curve CC
CC
CTRS Compound Curve
Compound Transition
CTRS
Compound Transition Point
Circular Curve Reverse curve
TRS Transition
Common Tangent Point
CTP Transition TRS
CC
Circular Curve
Figure 212 – Basic track geometry The various forms curves take in track layouts are:
© Rail Corporation Issued June 2012
1.
Simple curves.
2.
Compound curves.
3.
Reverse curves with length of straight.
4.
Direct reverse curves.
5.
Transition curves.
UNCONTROLLED WHEN PRINTED
Page 113 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
C8-2.1
TMC 202
Circular Curve (Arc) A Circular curve is a curve with a constant radius. Simple curves are of one radius between their tangent points with straights and are used to provide a change of direction. With flat curves, the change of direction at the tangent point is very gradual, but as the radius decreases and the curves become sharper, the rate of change of direction increases rapidly and introduces several unfavourable conditions from the action of vehicles entering the curve. These conditions make sharp circular curves unsuitable for high speeds, and can only be overcome by the introduction of “transitions”.
C8-2.2
Compound Curve A Compound curve is a curve formed when 2 or more circular curves of different radii are joined so that they follow the same direction. When flat and sharp curves are compounded similar conditions are set up at the compound tangent point as at the tangent points of simple curves due to the alteration of change of direction caused by the difference of radius. When the difference in radius is not great, compound curves are satisfactory, but where large differences occur transitions are necessary to remove these conditions. The limits of change of radius for compound curves vary with the maximum permissible speed for the line.
C8-2.3
Reverse Curve A Reverse curve is a curve formed when 2 curves (circular or compound) are joined so that the direction is changed. Where a length of straight occurs between the two curves it is desirable that it should be sufficiently long to allow vehicles to complete one change of direction before commencing the other; so that the minimum length should be at least equal to the overall length of the longest vehicle. Direct reverse curves should be avoided where possible in favour of a layout including a length of straight as above, owing to the undesirable reverse in change of direction.
C8-2.4
Transition Transitions are curves of gradually changing radius introduced between straights and circular curves, and between compound circular curves to make the change of direction gradual and to simplify the application of “superelevation”. The form of transition curve adopted on this system is described as a Cubic Parabola. The transition commences from the straight as a curve of infinite radius (that is, a radius so great that the curve may be considered straight), and the radius decreases gradually until it coincides with the radius of the circular curve which it joins. This provides a gradual uniform rate of change of direction between the straight and the circular curve and removes the effect of the abrupt change which occurs at the tangent point of circular curves.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 114 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Due to the gradual change of radius, transition curves allow the application of superelevation that matches the radius as it changes.
C8-2.5
Superelevation This is the deliberate raising of the outer rail above the level of the inner rail on curves, to even out the centrifugal forces, allowing faster speeds, smoother running and less wear and tear. When there are variations in superelevation on curves the chances of a derailment are greater. This is because the rolling stock lack a differential and so want to run straight ahead. The amount of superelevation at any point in the transition is based on the radius of the curve and the required average speed of trains around the curve. Curve charts or “F Sheets” (also known as “G” sheets) are available and show details of: • • • •
The radius of the curve. The amount of superelevation. The ramp rate (used to calculate the length of the transition). The location in kilometres of the TP and the TRS.
Superelevation is applied gradually and evenly from the straight to the curve to ensure trains travel smoothly. If incorrect superelevation is applied to the track the following can occur:
C8-3
1.
Increased wear on the low rail. This is caused by too much of superelevation being applied to curves.
2.
Increased wear on the high rail. This is caused by not enough superelevation on curves.
3.
Possible derailments. superelevation.
4.
Reduction in clearance. This can be caused by changes in super. eg. platforms, structures etc. Overhead wiring is also affected.
This can be caused by sudden changes in
Grade The term “Gradient”, more commonly called “grade”, is the rate of which the finished surface of a track rises or falls in its length. Grades are expressed as a percentage (%) indicating the rise in every 100 m of length. Thus, a grade of 2.5% (1 in 40) is a rise or fall of 2.5m in l00m of horizontal distance, as in Figure 214. The direction of a grade. is described with the direction of traffic as a “rising grade” or a “falling grade”, and with the increase or decrease of the rate of grade so it is referred to as a “steeper” or “flatter” grade respectively.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 115 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
1 Rising grade 2.5%
40 Figure 213 – Rising grade
60
Falling grade 1.67%
1
Figure 214 – Falling grade The steepest rising grade in the direction of traffic on any section of line is called the “ruling grade” and this determines the heaviest loads that can be hauled through the section by the various types of locomotives. The highest point on a grade is known as the “summit” or “top” of the grade and the commencement of a rising grade is called the “foot” or “bottom” of the grade. In cases where the grades meet eases are introduced between the angles of the grades.
C8-4
Track Geometry terms
C8-4.1
Datum rail This is the rail that is used as a reference when measuring the track. On TANGENT TRACK either track can be used as the datum rail although the DOWN rail is normally used. Make sure you use the same rail for the whole length of track being measured. On CURVED TRACK the inner or low rail is used as the datum rail when lifting and levelling. On CURVED TRACK the outer or high rail is used as the datum rail when lining track.
C8-4.2
Longitudinal rail level (Top) The level (height) of the rail when you look along its length. The common term used is "TOP." If there is too much variation in top the following can occur:
© Rail Corporation Issued June 2012
1.
Rough riding - Variation in longitudinal rail level causes rough riding and it results in higher maintenance of rolling stock.
2.
This also results in passenger discomfort and speed restrictions causing delays.
UNCONTROLLED WHEN PRINTED
Page 116 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
C8-4.3
TMC 202
Rail level Rail level is the height of the running surface (top) of the rail when it is measured to survey marks.
C8-4.4
Rail level
Cross level
Cross-level This is the level of one rail compared to the other when you measure across the track.
C8-4.5
Twist This is a variation in cross level when measured at different points along the track (usually every 2 metres for a short twist and every 14 metres for a long twist.) If twists are left in the track the following can occur: • Derailments - Because of the rigid nature of the track and vehicle suspensions the wheel travel cannot compensate for sudden changes in cross-level and the wheel may “float” and derail. • Oscillations or swaying movements (rock and roll) - This swaying of rolling stock may result in derailments. • Increased track maintenance - The pounding of track from the rolling stock as it travels along is increased, resulting in more rail wear and more maintenance.
C8-4.6
Track gauge The track gauge is the distance between the two rails of a track. The standard gauge is 1435mm. It is measured between the two gauge faces 16mm below the running surface.
C8-4.7
Survey Tells us exactly where the track should be (alignment and rail level). For alignment measurement, the datum rail is normally the closest rail to the survey mark. For alignment measurement, the datum rail is the low rail on curves.
C8-4.8
Alignment This is the horizontal (or lateral) position of the track as compared with the permanent survey marks and is measured using a plum bob and tape from the gauge face of the nearest rail to the survey mark.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Alignment
Page 117 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
9 Good track alignment Correct alignment distance
8 Poor track alignment Incorrect alignment distance
Survey Mark
98
98
Figure 215 - Good track line - Poor track alignment
C8-4.9
Line This is the horizontal smoothness of the track, without reference to the permanent survey marks. The datum rail is the high rail on curves and either rail on straight track. 9 Good track line
8 Poor track line Survey Mark
9
9
9
Figure 216 - Good track alignment - Poor track line
C8-4.10
Track Centres This is the distance between two tracks and is measured from centre line to centre line or from one rail of one track to the corresponding rail of the other track. Track Centres
C8-4.11
Structure Clearance Is the distance from a fixed object at the side of the track to the centre line of the track and is normally measured from the closest point of the structure to the gauge face of the nearest rail.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Structure Clearance
Page 118 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Chapter 9 Measuring Track Geometry C9-1
Use of Non Metallic tapes Using metallic tapes can result in electrocution or track circuit failures. Some of the safety risks include: • Electrocution from overhead wiring and high voltage lines and making contact between rails and overhead wiring structures. • Small electric shocks from track circuit voltages. Some of the reliability risks include: • Signal failures due to short circuit across the track. • Signal failure due to short circuit across insulated joints (both open track and turnouts). • Tripping of trains at line speed. DO NOT use Steel tapes, metal reinforced linen tapes and long steel rules when taking measurements: • • • •
Between rails of same or different tracks. Near live exposed electrical equipment. Between rail and overhead wiring structures. Between OHW structures and fencing or metallic troughing.
Only use non-conducting tapes and sticks that have been electrically tested, approved and branded, when working around electrical equipment. If you have to use metallic objects, conduct an assessment of the potential risks (both for safety and reliability) involved.
C9-2
Using a level board
C9-2.1
Types of cross level boards There are now many types of cross level boards available for use. All these boards allow you to measure cross level / superelevation and most also measure gauge. Supervisors board It is made of stainless steel and is used to measure cross level and gauge. The board must be rotated 1800 for a negative reading. These boards do not have an adjustable spirit level so therefore cannot be easily calibrated. Combination board Made of timber with an adjustable aluminium measuring arm. It can be used to measure cross level, gauge, rail level and alignment. The board must be rotated 1800 for a negative reading.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 119 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
This board does not have an adjustable spirit level and is not often used these days. “Robel” board; “Giesmar” board; “Sola” board These types of boards are the most common in use today. They are made of aluminium and have a spirit level that can be adjusted by a dial divided into millimetres to read superelevation. The gauge end of the board sits on the datum rail.
Figure 217 – One type of cross level board
Figure 218 – Spirit level and adjustable dial for super measurement
C9-2.2
C9-2.3
How to check for accuracy 1.
Find a point on the track where the cross level is close to zero.
2.
Place the board on the track and measure the cross level.
3.
Rotate the board 180° and measure the cross level.
4.
If the +ve reading and the -ve readings are the same then the board is accurate.
5.
If the +ve reading and the -ve readings are different, then the cross level board is not accurate.
How to adjust for correct reading
© Rail Corporation Issued June 2012
1.
Find a point on the track where the cross level is close to zero.
2.
Place the board on the track and set the scale (in millimetres) and the bubble to zero.
3.
Rotate the board 180° and measure the super.
4.
Halve the difference between what you have measured and zero.
UNCONTROLLED WHEN PRINTED
Page 120 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
C9-3
TMC 202
5.
Set the scale to this “new” number and then re-zero the bubble.
6.
Rotate the board 180° and check that the board reads the opposite. (If it is reading +10 one way, it should read –10 the other way).
Measuring gauge Gauge is measured 16mm below the top of the rail. Where gauge variation is suspected: 1.
Check gauge at 2m intervals with an accurate gauge board and record details of measurements. The rails must be bearing against the outside holding device before measurement.
Figure 219 - Measuring gauge with a tape When assessing tight gauge, flow is to be included. When assessing wide gauge use the gauge point as reference excluding flow. The principle is that the worst potential case needs to be measured. Rail flow provides the worst scenario for tight gauge. When measuring wide gauge, any flow lip may detach at any time, meaning that the gauge point will become the widest point. WARNING There are two types of measuring board available: One type has straight lugs that sit against the rail flow. The second type has a machined lug that measures at the gauge point under the rail flow. When flow is present this could result in measurement differences of up to approx 5mm between the two boards. To measure the rail gauge using an accurate Gauge Board:
© Rail Corporation Issued June 2012
1.
Place the Gauge Board across the rails at right angles. Allow the spring-loaded end to rest tightly against the gauge face of the rail.
2.
Read the measurement of the gauge from the scale provided on the board.
UNCONTROLLED WHEN PRINTED
Page 121 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
3.
TMC 202
Assess any rail play that is evident and add this to the static gauge as measured. This will ensure that the gauge as measured accurately reflects the true loaded gauge at the location.
To check for rail play: 1.
Examine the upper surface of the tie. If there is any evidence of the sleeper plates moving then the gauge may not be secure.
2.
Additional rail play can arise due to: o Movement between rail foot and edge of plate or fastening. o Movement between lockspike and plate. Such possible movements need to be considered in the assessment of gauge and gauge security. Areas where rapid failure is possible must have urgent action taken to secure the track against potential spread even if the actual measured gauge falls within allowable tolerances.
When rail wear is present it is sometimes necessary to measure the foot gauge (See Figure 220).
Figure 220 - Measuring foot gauge
C9-4
Measuring cross-level/superelevation Measure cross level and superelevation with an accurate standard track combination gauge and level. Other devices may be used to determine cross level, but their accuracy should be determined by comparison with an accurate standard combination track gauge and level. Where cross-level variation is suspected: 1.
Check and record cross-level values at 2m intervals.
2.
Calculate the variation value between each 2m interval and at 14m intervals.
3.
Obvious weak spots such as joints should be separately measured and assessed.
To measure cross level using an accurate gauge and cross level board: 1.
© Rail Corporation Issued June 2012
Check that the board is correctly calibrated. A correctly calibrated board should measure an opposite reading when reversed 180° in the same location e.g. +15 and –15.
UNCONTROLLED WHEN PRINTED
Page 122 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
C9-5
TMC 202
2.
Use the correct datum rail. This is the down rail on tangent track and the low rail on curves.
3.
Place the board across the rails at right angles ensuing both ends sit securely on the top of the rail head.
4.
Turn the superelevation dial until the bubble is centred.
5.
Record the measurement as displayed on the board insuring that they are recorded as + or -.
Measuring alignment Measure alignment to survey marks from the gauge face of the nearest rail. The outer rail of curves is the line rail. On tangent track, either rail may be used as the line rail, but the same rail shall be used throughout the tangent. Using a Measuring Tape and Plumb Bob: 1.
Locate the first survey mark in the area that you consider requires measurement. Check the mark to determine whether the distance of the track alignment is marked on it. If it isn’t, you may need to check with the CME's office before you start measuring.
2.
Mark the point on the rail that is square to the survey mark. To do this accurately, have someone hold one end of your tape measure or string against the survey mark. Move the other end backwards and forwards on the rail until you identify the shortest distance between the survey mark and the rail.
© Rail Corporation Issued June 2012
3.
Have someone place the zero mark of the tape measure on the survey mark or the rail (whichever is highest) and hold it there.
4.
Drop your plumb bob down on the other mark and extend the tape out to just past the plumb bob line.
5.
With your eye carefully positioned over the top of the plumb bob line, place the tape next to the line. Move the tape slowly up and down the string until you find the smallest measurement that lines up with the plumb bob line. This line is the distance from the survey mark to the rail.
6.
Repeat this procedure for all of the survey marks around the curve, or over the distance that you wish to measure.
UNCONTROLLED WHEN PRINTED
Page 123 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Figure 221 - Measuring alignment
C9-6
Measuring line Measure line of the line rail using stringlining methods. The outer rail (or high rail) of curves is the line rail. On tangent track, either rail may be used as the line rail, but the same rail shall be used throughout the tangent. Measure offsets in mm to the nearest 1mm. Where visible irregularities are evident:
© Rail Corporation Issued June 2012
1.
Visually locate the central point of the alignment irregularity.
2.
Using a 5 metre tape measure, measure off and mark four 2 metre intervals on each side of the central point of the irregularity. This will produce 8 measurement intervals about the trouble spot.
3.
Number each measurement station. The central point of the irregularity will be station No.5.
4.
Stretch an 8m stringline from station No.1 to station No.5, making sure the string is referenced to the gauge face of the line rail at a point 16mm below the running surface.
5.
Measure and record the distance from the string to the gauge face of the rail (16mm below the running surface) at station No.3. This is the middle ordinate measurement for station No.3.
6.
Move the stringline forward and stretch it from station No.2 to station No.6. Measure and record the middle ordinate opposite station No.4.
7.
Move the stringline forward and stretch it from station No.3 to station No.7. Measure and record the middle ordinate opposite station No.5.
8.
Move the stringline forward and stretch it from station No.4 to station No.8. Measure and record the middle ordinate opposite station No.6.
UNCONTROLLED WHEN PRINTED
Page 124 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
9.
Move the stringline forward once more stretching it from station No.5 to station No.9. Measure and record the middle ordinate opposite station No.7.
10.
You will now have mid-ordinate measurements from station No.3 to station No 7 (5 measurements).
11.
Where alignment irregularities cover a significant length of track, increase the number of measurement stations. As a general rule, stringlining should cover a distance of at least 8m either side of any noticeable irregularity in track alignment.
Figure 222 – Measuring line If a radius rule is not available, measure the versine in mm and determine the radius from Table 2 below. Middle Ordinate mm 4.0 5.5 8.0 9.0 10.0 11.5 13.5 14.5 16.0 16.5 17.5 18.0
Radius m 2,000 1,500 1,000 900 800 700 600 550 500 480 460 440
Middle Ordinate mm 19.0 20.0 21.0 22.0 23.5 25.0 26.5 28.5 31.0 33.5 36.5 40.0
Radius m 420 400 380 360 340 320 300 280 260 240 220 200
Middle Ordinate mm 42.0 44.5 47.0 50.0 53.5 57.0 61.5 66.5 73.0 80.0 89.0 100.0
Radius m 190 180 170 160 150 140 130 120 110 100 90 80
Table 2 – Versine and Radius measurements © Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 125 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
As in Table 2, the radius can be calculated for an 8 metre chord using the formula:
R=
8000 V Where R = and V =
C9-7
Radius of curve in metres Middle ordinate in millimetres
Rail Level Using a Level Board or string and bubble:
C9-8
1.
Locate the survey mark that you wish to measure from.
2.
Put one end of the Level Board (or string) on the survey mark or the rail (whichever is highest) and have someone hold it there.
3.
Hold the other end level and square to the rail.
4.
Measure the distance down to the survey mark or the rail (whichever is lowest) with a tape measure remembering to keep the Level Board (or string) level.
5.
When you are measuring rail level, the lower rail is the datum rail, If you have measured the higher rail with the process listed above, you should now measure the difference in cross level or superelevation of the two rails. This measurement must be subtracted from your rail level measurement, to give the level of the datum rail above or below the survey mark.
Rail Top Measure longitudinal level with a chord of specified length. Take the measurement at the centre of the head. Where visible irregularities are evident:
© Rail Corporation Issued June 2012
1.
Visually locate the central point of the rail top irregularity. This will often be a joint.
2.
Using a 5m tape measure, measure off and mark two 3 metre stations on each side of the central point of the irregularity. This will produce 4 measurement intervals about the trouble spot.
3.
Number each measurement station. The central point of the irregularity will be station No.3.
4.
Stretch a 6m stringline from station No.1 to station No.3, making sure the stringline contacts the running surface in the middle of the rail head at each end of the stringline.
5.
Measure and record the distance from the string to the middle of the rail head at station No.2.
6.
Move the stringline forward and stretch it from station No.2 to station No.4. Measure and record the middle ordinate opposite station No.3.
7.
Move the stringline forward once more stretching it from station No.3 to station No.5. Measure and record the middle ordinate opposite station No.4.
UNCONTROLLED WHEN PRINTED
Page 126 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
8.
C9-9
TMC 202
Where top irregularities cover a significant length of track, increase the number of measurement stations. As a general rule, stringlining should cover a distance of at least 6m either side of any noticeable irregularity in rail top.
Clearance to structures Using a Measuring Tape and Plumb Bob: 1.
Locate the survey mark that you wish to measure from.
2.
Mark the point on the near rail that is square to the survey mark. To do this accurately, have someone hold one end of your tape measure or string against the survey mark. Move the other end backwards and forwards on the rail until you identify the shortest distance between the survey mark and the rail.
3.
Have someone place the zero mark of the tape measure on the survey mark or the rail (whichever is highest) and hold it there.
4.
Drop your plumb bob down on the other mark and extend the tape out to just past the plumb bob line.
5.
With your eye carefully positioned over the top of the plumb bob line, place the tape next to the line. Move the tape slowly up and down the string until you find the smallest measurement that lines up with the plumb bob line. This line is the distance from the survey mark to the rail.
6.
Record this measurement.
7.
Repeat this procedure for all of the survey marks over the distance that you wish to measure.
8.
To determine the distance to the track centreline, add 718mm (half of a gauge measurement) to the measurement on the scale.
Figure 223 – Measuring Structure Clearances
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 127 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
C9-10
TMC 202
Track centres Using a non-conductive tape measure (e.g. cloth, fibreglass): 1.
Measure the distance from the gauge face of one rail of one track to the gauge face of the corresponding rail on the adjacent track.
2.
DO NOT measure adjacent rails of two adjacent tracks.
Figure 224 – Measuring Track Centres
C9-11
Measuring turnouts A “Combination points and crossing, track gauge and cant measuring device” is available that will directly measure gauge, checkrail effectiveness, flangeway clearance and superelevation. The board will measure over the top of raised checkrails. General use details 1.
Fixed Support
Flangeway dial
Place the board on the track with the fixed support on the checkrail carrier or “K” crossing wing and the Telescopic Support (the end with 2 dials) against the crossing nose running face. Handle
Superelevation Dial
Gauge Dial
Checkrail Effectiveness Dial Gauge Knob (2)
Flangeway measurement cursor
Superelevation Knob (1)
Telescopic Support
Figure 225 – Turnout measuring board
© Rail Corporation Issued June 2012
2.
Measure Superelevation using Knob (1) in a similar way to other gauge boards in service.
3.
Measure gauge by winding knob (2) until light resistance is felt and both edges of the board supports are resting against the gauge faces. Read the Gauge Dial (the inside dial of the pair of dials).
UNCONTROLLED WHEN PRINTED
Page 128 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
4.
Measure Checkrail effectiveness by placing gauge in position where gauge was measured (see Step 3).
5.
Grip the handle and firmly slide the gauge board sideways towards the crossing nose until the flangeway measurement cursor rests against the checkrail. Ensure that the other end rests against the crossing nose and read the distance from the outer dial of the pair of dials. If knob (2) has to be turned, make sure that the fixed support end does not move away from the checkrail face.
Checkrail Effectiveness Dial Gauge dial
Gauge Knob (2)
Figure 226 - Gauge and checkrail effectiveness measurement 6.
Measure flangeway clearance by holding the gauge against the checkrail carrier vertical face and move the lever hard towards the checkrail. When both rail faces are in contact with the gauge support, the dial above the checkrail displays the flangeway measurement. Flangeway dial
Flangeway measurement cursor
Figure 227 – Flangeway measurement Calibration
© Rail Corporation Issued June 2012
1.
Check the length measurement periodically against a calibrated tape to confirm the dial measurements are within +/- 1mm
2.
Check the superelevation reading on level track by reversing the board as with current combination boards.
UNCONTROLLED WHEN PRINTED
Page 129 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Chapter 10 Track Inspection Railway track is constructed from various components. Each of these components (rails, fastenings that attach the rails to sleepers, stone ballast that supports the sleepers and the embankments on which the ballast rests) wear out with usage or age and must be replaced when their condition can no longer be managed with a reasonable level of assurance of safety. To assure the on-going safety of the track and to effectively manage the condition, repair and replacement of components, RailCorp carries out a schedule of inspections. Each inspection targets identified aspects of track and is carried out at a frequency that has been established through analysis and experience to identify signs of the track wearing out or varying from design. These inspections allow RailCorp staff to program repairs whilst the track is still safe for normal operation. The inspections include:
C10-1
Track Patrol A visual inspection of the track either by hi-rail vehicle at slow speed, or by walking in areas where hi-rail vehicles are not allowed to operate (basically the inner Metropolitan and Newcastle CBD areas). Generally the track is patrolled twice a week on passenger lines and heavy freight lines. Lightly trafficked freight lines are patrolled less often. The patrollers look for signs that the track is deteriorating, particularly where immediate action is required to maintain track safety. This involves looking for obstructions, track geometry defects, broken rails, signs of earthworks or drainage failure and the visibility and security of track signage. Detailed inspection is undertaken during the patrol when visual signs are identified. At some locations a proportion of the walking patrol has been replaced by Engine Patrols in which patrollers ride the front of trains and examine for defects. Any identified defects are inspected on-foot at the end of the Engine Patrol. Patrol staff will take action to protect the track (stop or slow down trains) if bad defects are found.
C10-2
Mechanised Track Patrol Some walking patrols have been replaced by Mechanised Track Patrol. This patrol is conducted with a vehicle fitted with multiple video cameras that record views from fence to fence, of a specific track and of the inside and outside of individual rails. A patroller rides the vehicle to mark points of interest (potential defects) and reviews the recorded images in detail after the run.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 130 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Figure 228 – MTP vehicle
Figure 229 – Screens used for Detailed Review of defects
Figure 230 - Views available from MTP cameras
C10-3
Detailed Walking Inspection A walking inspection of track is conducted every 3 months to view the track behavior in detail. This inspection provides information on the condition of all aspects of the track and its components.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 131 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
C10-4
TMC 202
Engine Inspection Every two weeks in the Metropolitan area an inspection is conducted from the cab of a train to assess the effect of track condition on the ride comfort of trains. Some types of track geometry variations are best found by this inspection. The inspection is also an opportunity for track staff to find out from train crew areas that drivers consider need attention.
C10-5
Detailed Examinations Specific elements of track are examined, measured and recorded at 6 monthly, yearly or 2 yearly intervals. The elements include turnouts, insulated rail joints (which are essential components of the signalling system), rails, lubrication, level crossings, drainage and clearance to structures beside and above the track. The examinations form an important part of the process of measuring condition, assessing performance and determining how quickly the different parts of the track are wearing out. The extent and timing of repair and replacement is determined from the information recorded.
C10-6
Track Geometry Recording Car The rail mounted recording car (commonly known as the AK car) operates on Metropolitan lines every 4 months. It records the condition of the track geometry, compares it to established standards and provides real time information to track staff of locations where maintenance work is required to correct variations in top, twist, alignment and gauge (the distance between the rails). The recording software also applies statistical techniques to assess the overall condition in comparison to standards and other locations in the RailCorp network.
Figure 231 – Track Recording Car
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 132 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Figure 232 – Track Geometry recording
C10-7
Rail Flaw Detection The visual examinations detailed above cannot find defects inside the rails. Testing of rail to detect microscopic internal defects is conducted by ultrasonic testing with the Rail Flaw Detection vehicle. The testing is undertaken every 4 months in most areas of RailCorp, less frequently on lightly trafficked lines. Because of the incidence of Vertical Split Head (VSH) defects in 2002 some sections of track are now tested every 2 months. Some areas of track, particularly in turnouts, cannot be tested by the Rail Flaw Detection vehicle. These are tested every 6 months by staff using portable ultrasonic and magnetic particle testing equipment.
Figure 233 – Rail Flaw Detection Car
© Rail Corporation Issued June 2012
Figure 234 - Rail Flaw Detection trolley
UNCONTROLLED WHEN PRINTED
Page 133 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
C10-8
TMC 202
Misalignment Prevention When rail track heats up in extreme summer temperatures it will misalign (also known as a buckle) if it is not properly controlled. RailCorp track is designed to resist buckling at high temperatures by maintaining the right amount of rail in track, stopping the rail from moving and bunching up and providing resistance to the sideways movement that occurs when track buckles. To provide assurance that the design conditions are maintained during the summer period track stability examination, analysis and correction are conducted between August and October each year. This involves inspection of rail adjustment, ballast profile and condition, fastening condition and areas of potential concern, analysis of the contribution of these factors to the overall stability and programmed, prioritised improvement at identified locations.
C10-9
Heat Patrol During the hotter months of the year, when temperatures reach 380C, staff conduct patrols of the track to detect early signs of instability leading to misalignments. These patrols are normally conducted by hi-rail or the front of a train so that track can be inspected in a short period of time in the hottest part of the day.
C10-10
Out of Course Inspections In addition to the programmed inspections mentioned above, RailCorp staff conduct special inspections of track in periods of extreme rainfall and flooding, bushfires and at locations where track conditions warrant more frequent monitoring, to provide assurance of the on-going safety of the infrastructure. More information on track inspection practices can be found in Engineering Manual TMC 203 – Track Inspection.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 134 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Chapter 11 Track Maintenance Practice Track is a system in which individual components (earthworks, ballast, sleepers, fastenings and rail are combined to support the loads imposed by trains, to provide a path for signalling circuits and to provide a safe return path for electric traction currents in electrified areas. It is not maintenance free. Each of these components deteriorate under the cyclic loading of wheels, or due to environmental conditions. When individual components degrade or fail they have an impact on the performance of other components, either by increasing the loads and stresses on the other components or by failing to provide other components with support. Good maintenance practice requires an understanding of how and why components fail, how they interact and what constitutes good repair and replacement practice. This chapter provides some guidance on these topics and includes reference to detailed installation and repair practices in RailCorp’s Engineering Manuals.
C11-1
Geometry The line and level of rail track is designed, with straights (also called tangents) and curves in the horizontal plane and grades and vertical curves in the vertical plane. Changes of horizontal curvature are accompanied by changes of superelevation. Transitions with gradual changes of curvature and superelevation are used to join tangents and curves. The amount of superelevation applied and the rate of change of superelevation will be within limits detailed in Engineering Manual TMC 211 – Track Geometry and Stability. Track line, superelevation and level may vary from design over time. It should be maintained within the limits detailed in Engineering Manual TMC 211 – Track Geometry and Stability. Poorly maintained track geometry (top, line, twist or superelevation) could cause: • passenger discomfort through rough riding, • increase the impact loads on the track components leading to rail wear, battered joints and dipped welds, and failure of sleepers, fastenings, ballast and formation, • incorrect adjustment of the rails through poor alignment on curves, • incorrect track centres and structure clearances through incorrect superelevation and alignment. In extreme circumstances this may cause a derailment by altering the distribution of the wheel loads of the rolling stock and allowing the leading outer wheel of a vehicle to climb the outer rail. Poor geometry is usually visible but in some cases what appears to be good top will pump under vehicle load with the result that trains will experience poor top or twists. Poor top may be caused by: • Lack of maintenance, especially in areas prone to higher degradation (eg rail joints and bridge ends). • Degraded ballast or formation allowing the sleepers to move down under load. • Rail conditions such as corrugations, wheel burns, squats, battered rail joints or dipped or poorly ground welds.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 135 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
• Track settling after installation or maintenance. • Geotechnical settlement and variation. • Loss of sleeper support (unusual in RailCorp). Poor line is caused by: • Track movement due to hot or cold weather induced stresses after installation or maintenance, before track has achieved full lateral resistance. • Rail conditions such as poorly aligned welds and joints and irregularities in turnouts. • Degraded or poorly packed ballast or failed formation allowing the sleepers to move sideways under load. • Geotechnical settlement and variation. • Loss of sleeper support through loose fastenings or poor sleepers allowing rail and plate play under load, or irregular gauge. (unusual in RailCorp). Correct geometry maintenance will prevent or delay the need for additional maintenance. Correcting track geometry faults is not, generally, just a matter of bringing in resurfacing machines. If the cause of the defect is not addressed any improvement in geometry may only be temporary. • Where the geometry has deteriorated because of track formation failure or ballast degradation, reconditioning or ballast cleaning and drainage improvements may be required. • Track geometry defects caused by rail condition can only be corrected by rail or joint repair such as grinding, weld straightening, rail crowing, installation of closures or rerailing. • When geometry maintenance is carried out the work is not considered completed unless the track has been pulled to line, ballast has been replaced and the sleepers have been properly boxed up with ballast. • On main line track always align to survey marks. • Substantial pulling to realign curves will alter rail adjustment and Welded Track Stability should be checked before and after work to determine if rail adjustment is required and can be undertaken. Correct rail and joint maintenance will prevent problems arising. • When welding short closures into curves, cut the closure from rail which conforms as closely as possible to the curve wear on the existing rails and for curves of 800m radius and under crow the closure and each adjacent rail to the correct curvature. • Fishplated joints generally require considerably more fettling than the rest of the track and should be given special attention. Notes
© Rail Corporation Issued June 2012
1.
The procedure for rail adjustment is laid down in Engineering Manual TMC 223 – Rail Adjustment.
2.
If the track needs to be lifted and lined to restore track geometry, you need to consider structure, platform and overhead wiring clearances.
3.
Unstable track generally requires passage of ~200,000 tonnes of traffic or consolidation by a dynamic track stabiliser to regain stability.
4.
Track geometry maintenance practices are detailed in Engineering Manual TMC 211 – Track Geometry & Stability.
UNCONTROLLED WHEN PRINTED
Page 136 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
C11-2
TMC 202
Rail Rail is the interface between the train wheel and the track. It must be • Strong enough to take the wheel load acting vertically and laterally on the rail and the longitudinal stresses caused by hot and cold weather. • Hard enough so that it doesn’t wear out too quickly, but not so hard that it is brittle and wont bend. • Have the correct profile to control contact stresses and so that the forces from the wheel are directed properly through the rail to the sleeper. If rail condition is well maintained it is normally capable of lasting in track for a 1,000 million tonnes of traffic or more. Rail defects may arise from inclusions and micro cracks (internal defects) present in the rail at manufacture. Whether these microcracks grow to become rail defects or broken rails depends on the dynamic load of the wheel on rail. The dynamic load is increased significantly by: • Rail surface irregularities such as wheelburns, dipped welds, joints and corrugations. • Poor track condition, including failed sleepers, poor top and line, poor formation or other conditions that increase impact loads. • Flat spots on wheels of trains that increase impact loads. Rail defects may also occur in ‘clean’ rail. These defects may arise from rail contact fatigue, wheel burns, weld defects, corrosion, spark erosion or from impact and notches caused by track machines or poor work practices with tools (hammers). Detailed explanation of the many types of defects is found in Engineering Manual TMC 226 - Rail Defects Handbook. Most rail wear occurs on the gauge face of the high rail in curves. As a rail wheel travels around a curve, the flange of the wheel is forced against the rail. The friction causes wear of the wheel and rail. Eventually the rail will wear so much that it must be replaced. The effort in track maintenance is aimed at: • Controlling the forces on the rail that generate rail defects. • Controlling rail wear so that rails will last longer before they need replacement. • Detecting and removing defects before they grow to a critical size. Controlling the forces This is achieved by maintaining good track geometry and by rail grinding and surface defect removal. Any geometry defect will increase the impact forces and overstress the rail in the region of internal defects. Maintain good top and line, well packed, sound sleepers and clean ballast. Surface defects, whether they are large, like wheel burns or large squats, or small, like RCF defects, increase the impact load. Rail grinding should be used to remove rail surface defects. If they are too big, head repair by wirefeed welding or aluminothermic head repair welding may be appropriate. If this is not viable, the rail section will need to be replaced. Rail welding practices are detailed in Engineering Manual TMC 222 - Rail Welding. Rail grinding is also used to apply a designed profile to the rail head. The profile has been designed to maintain the contact area between the wheel and rail as close to the centre of the rail head as possible. This reduces the development of defects. Rail grinding practices are detailed in Engineering Manual TMC 225 – Rail Grinding.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 137 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Controlling rail wear Rail wear on the gauge face is controlled by improving rail hardness, by rail grinding and by rail lubrication. Head hardened rail wears significantly less than standard carbon rail and is installed in most curved areas in RailCorp. Rail grinding applies a designed profile that assists bogie steering on curves, reducing wheel flange contact on the gauge face of the rail. On sharp to medium radius curves, the friction between the wheel flange and the gauge face of the rail is controlled by applying rail lubricant (grease) to the gauge face of the rail. Rail Lubrication When a vehicle goes around a curve, the outside wheel flanges push against the gauge face of the outside rail and causes friction. This friction causes curve wear on the gauge face of the high rail. It also causes wear on the wheel flanges of the rolling stock. Effective lubrication of the gauge face helps to reduce wear. Contamination of the running surface of the rail with grease is not allowed as this can cause slipping of wheels and rail head contamination. As the trains approach the curve the wheels run over the small plungers of the lubricator that pumps the grease to the blades to be picked up by the wheel flanges and distributed on the gauge face of the rails throughout the following curves. Rail lubrication is not normally needed on curves above 600 - 800m radius. The performance of the lubricator depends on sleeper type, general track condition, grades, type of traffic, environmental concerns, type and location of lubricator, and type of grease used. The use of high performance grease, the specific placement of the lubricator and regular adjustment and maintenance has allowed for more efficient use of the lubricator. Distribution of grease along the rail can be effective up to 8 - 10km in timber track and up to 5 - 6km in concrete track with moderate grade and curvature. Rail lubricators should be situated to provide effective coverage for the curves requiring protection from rail wear. The most important factor in grease distribution is the location of the lubricator, which should be placed in the transition of the curve, at the start of the wheel flange contact on the gauge face of the rail. When possible, lubricators should be positioned in moderate radius feeder curves ahead of the sharper curves that are the main target. Well maintained lubrication should demonstrate no loss of traction between rail and wheel indicating too much lubrication; no excessive curve wear; shiny wear marks on the gauge face and/or steel shavings along the rail foot indicating insufficient lubrication. When significant curve wear occurs the condition, location and spacing of lubricators needs to be investigated. Lubricators should not run out of grease, nor should they pump out too much or too little grease onto the track. When this occurs, lubricators need to be filled, adjusted or repaired. Rail Lubrication practices are explained in further detail in Engineering Manual TMC 221 – Rail Installation & Repair.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 138 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Detecting and removing defects There are 3 methods of locating rail defects: • Ultrasonic testing by a special rail mounted vehicle (Speno Car). • Ultrasonic testing with portable testing units. • Visual location of defects or potential locations where defects may form. Track Inspection practices are aimed at finding defects before they grow to a broken rail. When defects are detected there are mandatory protection and removal requirements. More detail on defect detection practices is provided in Engineering Manual TMC 224 – Rail Defects & Testing and in Engineering Manual TMC 203 – Track Inspection. Visual location of defects or potential locations where defects may form is an important part of the inspection and maintenance procedures. Breaks or cracks in the rail are normally found around rail ends, joints, rail welds, turnouts etc. When broken rails occur, because most rails are part of track circuits that operate the signalling system, the track circuit will be cut and signals will turn red and stop trains. This is not, however, always the case. Some rails in turnouts and plain track are not circuited and some rail breaks occur at points where the track circuits have been redirected (eg at mechanical joints where bond wires bridge around the joint gap). When a rail breaks in welded track it must be properly secured with fishplates and reported immediately. If the break is such that traffic cannot be safely allowed over it, a closure must be cut or welded in as detailed in Engineering Manual TMC 221 – Rail Installation & Repair. In the event of an aluminothermic weld breaking or developing a crack, fit a pair of 'bow' plates at once. In the case of flashbutt welds breaking or developing cracks, fit a pair of special slotted and grooved plates. Rail Adjustment After mechanically jointed track is laid the expansion gaps need to be carefully adjusted. Any creep that occurs with welded track alters the correct adjustment of the gaps making some too tight and others too wide. When this causes an adjustment error, action is necessary to readjust the track. Similarly, continuous welded rail (CWR) is carefully adjusted at installation. Creep measurement marks are monitored as set out in Engineering Manual TMC 203 - Track Inspection and the necessary action taken to correct creep when it causes an adjustment error. Rail creep can occur from rails moving through fastenings or from rail and sleepers moving through the ballast. The adjustment process for CWR track is different from that applying to mechanically jointed track and is set out in detail in Engineering Manual TMC 223 – Rail Adjustment. A broken rail in CWR track will change the adjustment of the rail and make readjustment necessary at the completion of the work. This is usually carried out using the “Rail In = Rail Out” process. During the adjustment of CWR track, particular emphasis must be placed upon initial destressing of the rail and subsequent equalisation of adjustment stresses by vibrating
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 139 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
the rail. This is carried out using vibrating machines or tapping the web of the rail with hammers (hammer blows to the wrong part of the rail can cause broken rails). In timber sleepered dogspiked track rail anchors are provided to prevent creep and limit the movement of rails with the rise and fall of temperature. The standard of anchoring detailed in Engineering Manual TMC 221- Rail Installation & Repair is usually sufficient to prevent creep, but in certain locations, such as approaching stations, signals, or on heavy down grades, additional single anchors against creep are necessary and should be installed. Anchors must be maintained against the sleeper. Remove anchors found away from the sleeper and refix them against the sleeper. DO NOT hammer them along the rail.
C11-3
Rail Joints Generally RailCorp mainline track is continuously welded with no mechanical joints. Mechanical insulated joints have generally been replaced by Bonded or glued insulated joints. Some jointed track areas remain and they need to be maintained. Rail joint condition The rail joint is one of the weakest parts of the track structure. Rail joints need constant inspection and maintenance work, due to: • constant impact by rolling stock wheels, • compressive and tensile forces from rail movement. In turn poor joint condition increases the impact forces from train wheels and increase the vertical forces transmitted to sleepers and ballast. This leads to sleeper and fastening failure and ballast crushing and pumping. The track geometry at the joint is also affected. Poor geometry increases the impact load, …….and so the cycle continues. In a well maintained joint, the gauge faces are true and the rail ends are square and have no end batter, dip or rail flow. The rail ends open and close in the right temperature range. The fishplates have no cracks and are held firmly by 6 fishbolts. Sleepers are spaced closer together at joints and are well packed. Sleepers are sound and the fastenings are holding the sleeper plates and rail without movement. In dogspiked track, anchors are placed against the correct sleepers near the joint. When bolts become loose it may be because of wear or washers that have lost their spring. Mechanical joints are laid with a 6mm gap at rail neutral temperature (350C). Gaps should close up in hot weather and be fully open in cold weather. If they are open in hot weather or closed in cold weather, something is wrong and it needs to be investigated. It may be due to creep or frozen joints (the rails not moving in the fishplates due to rust or excessive tightness of bolts). In this case the fishplates need to be loosened and the joint lubricated. If bolts are bent, the rails are imposing too much longitudinal force on the joint and the track adjustment will need to be checked, including the adequacy of the anchors and whether the joint is frozen. If the geometry (top and line) of the joint is poor, the joint support is inadequate. The joint sleepers may have failed, but it is more likely that the ballast support has failed (either vibrated away from the joint or sunk into the failed formation) and the sleepers are pumping under load. If the sleepers are sound, and there is no evidence of formation
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 140 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
failure, the geometry can be corrected by removing any crushed ballast, laying some fresh ballast and packing the sleepers. If, however, the formation has failed, packing will only provide a temporary solution and the formation will need to be repaired. If the rail ends are bent down, are battered or chipped or there is rail flow, it is evidence that there are high impact forces on the joint. Metal flow on rail ends reduces the expansion allowance and also causes rail end chipping when rails close up during hot weather. These rail conditions can be corrected by wire feed welding or grinding but they will re-occur unless the high impact is reduced by correcting the joint geometry. When the sleepers fail under the joint, the fastenings cannot hold the rail and the joint will flog. Good sleepers are critical at joints. Replace any defective sleepers. More information on rail joint repair practices can be found in Engineering Manual TMC 221 – Rail Installation & Repair. Welds Rail welds are also a weak point in the track structure, although they are generally stronger than mechanical joints. Properly formed and cooled flashbutt welds are considered as strong as the parent rail. Aluminothermic welds do, however, lose their geometry under repeated loading because the heat affected material on either side of the weld is softer than the parent rail. The weld will eventually dip. This may be accelerated by poorly installed welds that have peaks or hollows, or in some locations by joint memory where a weld replaces an old joint that had poor geometry and the weld inherits this characteristic. Welds must be properly packed as part of the installation process. When welds dip, they may be corrected by replacement or weld straightening and grinding. The dips will generally be too large for grinding alone. Poor horizontal alignment of the weld can only be corrected by replacement. More information on rail welding practices can be found in Engineering Manual TMC 222 – Rail Welding. Mechanical Insulated joint condition Mechanical insulated joints are not expansion joints and the rail ends should be hard up against the key at all but very low temperatures. In cases where there is so much pull on the rails that the bolts bend and allow the gap to become excessive the track needs to be adjusted. In addition to maintenance practices in mechanical joints, insulated joints have insulating material at the rail ends, between the fishplates and rail and surrounding the fishbolts. All of these components wear under the imposed vertical, lateral and longitudinal forces. If the impact forces increase because of poor mechanical condition or geometry, the wear on the insulating components increases. When the insulation fails a signal failure will occur. Insulating components should be replaced if there is evidence of wear. If the rail end key is being squeezed out by the rail ends closing up in hot weather the track will need to be re-adjusted. If there is rail end flow debris across the key that could short circuit the joint it should be removed by grinding. More information on rail joint repair practices can be found in Engineering Manual TMC 221 – Rail Installation & Repair.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 141 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Bonded (Glued) Insulated Joint condition Glued insulated joints are not expansion joints. They are designed to act as part of the adjacent welded rail. Because they are bonded or glued together, they are stronger than mechanical insulated joints. They are not as strong as plain rail and will be affected by impact in the same way as mechanical joints. Track geometry at the joint needs to be well maintained and any signs of pumping corrected quickly by packing the sleepers and correcting top and line. If a glued insulated joint show signs of failure of the glue with a visible crack line at the endpost or under the fishplates, it should be replaced. Pending replacement, treat the joint as a mechanical insulated joint and anchor it accordingly. If there is any evidence of cracking or rust stains indicating cracking between the joint gap and the first bolt hole at the bottom of the plates, the joint needs to be replaced. Fastenings must be appropriate and must not cause signal failures (use low profile clips). If there is rail end flow debris across the key that could short circuit the joint it should be removed by grinding. Joints should also be kept clean of filings, steel scale and tin cans etc that could short out the joint. More information on rail joint repair practices can be found in Engineering Manual TMC 221 – Rail Installation & Repair.
C11-4
Sleepers Sleepers and fastenings are designed as a unit to form part of the total track structure. Their purpose is to: • Hold the rails at the correct gauge. • Spread the load from the rail to the ballast layer. • Restrain the rail from longitudinal movement. To satisfactorily meet the design requirements the sleeper and fastening combination must be: • • • •
Strong enough to accept the imposed loads. Solid enough to hold the fastenings and maintain the gauge. Correctly spaced and square, to transmit the load evenly to the ballast. Well packed to maintain the design top and line of the track.
The condition of sleepers and fastenings is critical to the control of stresses generated in welded track. The effort in track maintenance is to restore these capabilities to the sleeper fastening system when they have been lost. Sleeper life The life of timber sleepers depends on several factors including: • • • •
Type of timber. Drainage and climatic conditions. Traffic density, speed and axle loads. Track geometry and the standard of track maintenance.
In some areas they may only last 5 - 10 years but in other areas they may last 20-30 years.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 142 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Concrete sleepers are expected to last at least 50 years in well maintained track. The oldest concrete sleepers in RailCorp were installed in the mid 1980’s. The life of concrete sleepers depends on: • Axle loads and traffic volume. • Rail seat condition. • Rail condition, including wheel burns and other surface defects, and weld alignment. This causes loading on the sleepers due to impact resulting in sleepers breaking or cracking. • Track geometry. Sleepers and fastenings will need to be replaced or repaired in the following circumstances: Load support When timber sleepers become termite infested or rotten, or when they are crushed, broken, split or cracked they cannot support the load from the rails, nor can they support the fastenings. These sleepers need to be replaced. Concrete sleepers may be damaged in derailments or by maintenance activities. Generally cracking is not of significant concern unless it is in the rail seat area, in which case the sleeper will need to be replaced. On concrete sleepers rail seat pads are installed between the bottom of the rail and the sleeper to provide some cushioning and to reduce abrasion. Over time the pads will degrade and may need to be replaced. Insulators may also wear and crack, particularly on sharp curves. Rail seat abrasion in the concrete sleeper is rare in RailCorp. It can be repaired with epoxy concrete. Gauge holding When wide gauge occurs it changes the position of the wheels on the rail, which can lead to additional stresses in the rail, increased overturning stresses and, if wide enough, to a derailment. Wide gauge occurs because of rail wear on the high rail of curves, or because the cyclic dynamic loads wear and weaken the fastening system. Generally RailCorp has installed concrete sleepers in sharply curved track. widening due to plate play is not an issue in concrete areas.
Gauge
In some cases wide gauge on timber sleepers can be corrected by regauging and boring new holes for the fastenings as long as the sleeper is still sound in other respects. Replacing double shouldered plates with “Pandrol” plates and resilient fastenings can facilitate this process. If this is not possible, sleepers must be replaced. Spacing and skew Part of the structural design of the track is the spacing of individual sleepers. When spacing varies from design: Rail stresses increase because the supports for the rail are further apart. This will lead to increased defects in the rail. Sleeper, ballast and formation stresses increase because there are less sleepers to distribute the load from the rails. Whilst the effect of increased stresses on sleepers is generally inconsequential, increased load on the ballast can lead to increased settlement, degradation and movement, and eventual failure of the formation. The result of this is loss of top and line of the track and because the track pumps on the settled ballast, the bond with the ballast will be broken and resistance to misalignment is weakened.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 143 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Spacing can also affect the tamping operation, particularly if duomatic tampers are used. Sleeper skewing can damage fastenings and split timber. When poor spacing or skew is detected it should be corrected by respacing and squaring up. This may require inserting additional sleepers and spreading adjacent sleepers to achieve a consistent pattern. There are also limits on how close sleepers can be. If they are too close together they cannot be tamped. Spacing at bridge ends can be a particular problem. Packing Sleepers need to be firmly supported by ballast. The correct support is firmly packed ballast for the full length, except for 450mm in the centre, which must be loose packed with no hollows left. DO NOT pack ballast under the centre of sleepers. If this happens, sleepers can become centre-bound or end bound and they will break. Fastening condition and effectiveness Dogspikes, lockspikes, dogscrews, lockscrews and screwspikes are designed to hold the rail or sleeper plate firmly to the sleeper. They are non-resilient, ie they cannot accommodate any movement. In well maintained straight track with good top and line train loads are generally vertical and there is little, if any, lateral or uplift forces on the fastenings. Fastenings will remain tight. The sleepers, however, will eventually dry out and may release their grip on the fastenings. On curved track, however, and on track with poor geometry, lateral and uplift loads are imposed by the rail on the fastenings. These loads are cyclic and lead to accelerated failure of the spikes, or of the timber around the fastenings. Continued lateral loading leads to movement of the sleeper plate and gauge widening. It can also lead to back canting, where the outside edge of the sleeper plate digs into the sleeper, changing the rotation of the rail and widening the gauge. When dogspikes and lockspikes become loose new spikes need to be driven in new holes or the sleeper replaced. Spike holes in timber need to be drilled right through to allow moisture to pass through. If water is trapped in the spike hole, the spikes may corrode and fail without notice. Resilient fastenings Resilient fastenings hold the rail to the sleeper plate (or sleeper in concrete). They impose a positive vertical force on the rail foot and resist vertical and longitudinal rail movement. Lateral load is resisted by the spikes holding the sleeper plate to the sleeper (or the cast in shoulder in concrete). Where resilient fastenings are used in timber sleepers they replace dogspikes and rail anchors. Resilient fastenings can be very effective in increasing sleeper life. Resilient fastenings also give rise to other benefits, including: • • • •
© Rail Corporation Issued June 2012
Increased resistance to buckles and misalignments. Increased ballast and formation life. Reduced rail defects and broken rails. Reduced derailment risk from spread road and rail rollover.
UNCONTROLLED WHEN PRINTED
Page 144 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Resilient fastenings provide a positive fixing of rail to sleeper so that relative movements are generally minimal, which is beneficial in resisting the following failure modes: • • • • •
Wear of the timber under the rail plate, especially backcanting on curves. Movement of the fastening in the timber causing it to loosen. Wear at the interface between the pin fastening and the plate. Wear at the interface between the rail foot and the plate. Fatigue loading of fastenings.
The positive fixing of Resilient fastenings also gives a more consistent track structure with more uniform distribution of load to the sleepers (vertically, horizontally and rotationally). Notably this avoids the problem where the good sleepers tend to take the entire load and their failure is accelerated). The better loading distribution also means that track geometry holds up better so that the loads from the track to sleepers are reduced. The rail to sleeper situation is improved as well as the sleeper to ballast situation (ie sleeper degradation from ballast abrasion will be reduced). One other benefit to sleeper life applies because of the improved anchoring provided by elastic fastenings in that sleeper skewing is prevented. It is important to correctly install resilient fastenings so that they are driven fully home (but not overdriven) using the method appropriate to the type of fastening. DON’T overstress resilient fastenings by lifting rail off the sleeper plate with the fastenings in place, or by levering upward between the toe of the fastening and the foot of the rail. Clips can also be damaged by track maintenance activities. Remove all clips when adjusting or moving rail fitted with resilient fastenings. DO NOT try to pull rail through resilient fastenings. When resilient fastenings age they no longer provide adequate toe load. They cannot be repaired and need to be replaced. Concrete cast-in shoulders can be damaged by track maintenance activities, derailment or dragging equipment. They can be repaired, although in most cases it may be more practical to replace the sleeper. More information on sleeper and fastening repair and replacement methods can be found in Engineering Manual TMC 231 – Sleepers.
C11-5
Ballast Ballast is designed as a component of the total track structure to: • Support the sleepers at the designed geometry (top and line). • Spread the load from the underside of the sleepers to the formation. • Provide resistance to lateral and longitudinal movement. To satisfactorily meet the design requirements ballast must be: • Strong enough to resist crushing under loads. • Of the right material (type of rock) so that it can resist weathering. • Sharp and angular so that the stones will lock together, lock onto the sleeper and hold the track stable. • Graded to the right mix of stone sizes so that the spaces between the ballast are neither too large nor too small.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 145 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
• Free draining (not clogged by dirt and mud) so that it allows water to run through it and off into the drainage system. • Deep enough to spread the load from the sleepers. If it is not deep enough the load on the formation will eventually cause it to fail, and the formation material will pump through the ballast. This will result in poor track geometry and increased maintenance. • Not too deep so that it affects track stability. • Of the correct profile, including shoulder width and height of ballast in the sleeper cribs (400mm shoulder on main lines and full cribs), and well compacted so that it grips the sleeper and provides resistance to lateral and longitudinal movement. The effort in track maintenance is to restore these capabilities to the ballast when they have been lost. Ballast profile Ballast profile and depth are “topped up” by laying ballast during the resurfacing process or at other times when deficiencies are recognised. This is important in the Welded Track Stability Assessment process prior to summer. Where required, ballast should be laid prior to or during resurfacing operations, not afterwards. There should always be sufficient ballast on hand to complete resurfacing work, regulate and stabilise the ballast and leave a full ballast profile. Where ballast depth is inadequate, additional ballast can be supplied to lift the track, as long as there are no restrictions on the amount of lift. Overhead wiring and overbridges restrict track lifting. Where track cannot be lifted, additional ballast depth can only be obtained by lowering the formation. Excess ballast There can also be too much ballast on track. Ballast can foul signalling equipment especially at points and train stops. It can also foul rollingstock and cause tripping of trains. If sleepers and fastenings are not visible they cannot be inspected during examinations. Defects can be hidden. It is good maintenance practice to inspect track after ballast has been laid to make sure that there is no ballast fouling equipment. Excess ballast is removed either by ballast regulators, particularly if the area of excess is large, or in small delicate areas by hand shovelling, off track machines or vacuum equipment (supersuckers). Condition If ballast becomes fouled with mud and degraded ballast material, it loses its ability to provide drainage of water through the ballast down to the formation and into the drainage systems. The trapped water weakens the formation, resulting in soil from the formation rising in the formation and causing pumping track. Pumping track, in turn, affects track geometry and track stability. Ballast grading and material properties also have a significant impact on the performance of track. Poor drainage may result from poor grading or from soft, friable rock. Reduced track stability may result from poor interlocking in badly graded or shaped material. Ballast condition should be maintained by using the right grading and material, by keeping the drainage working, and by maintaining adequate ballast depth so that formation failure does not occur. © Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 146 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Ballast condition can only be improved by ballast cleaning or replacement. Whilst ballast abrasion does occur, most ballast condition failures are symptoms of poor drainage or formation. These must be corrected for any long lasting solution to be effective. Stability Track stability is significantly affected by the stability of ballast. A stable ballast layer has been vibrated so that individual stones have rotated and locked together, resisting further movement. Ballast underneath and to the sides of each sleeper, locks into the sleeper, creating further resistance to movement. If any work has been done to break the bond with the sleepers (e.g. releepering or resurfacing), or the interlocking of ballast stones has been disturbed (e.g. resurfacing, ballast cleaning etc), stability is not restored until ~200,000 tonnes of rail traffic has passed over the track or a track stabiliser has been used. Ballast stabilisers are often used as part of the resurfacing operation. More information on ballast replacement methods can be found in Engineering Manual TMC 241 – Ballast.
C11-6
Drainage Track is designed to stay dry. If water is trapped in the ballast and formation, the pumping action of trains running on the track will soften the formation causing “Bog” holes. This will degrade the ballast so that it cannot support the track. The track will lose top and line. Bog holes are usually identified by pumping sleepers, small mud geysers that form in the cess or ballast and a track that settles unevenly. These conditions produce a weakened track structure that requires constant maintenance. A weakened track structure results in heavy wear in the sleepers, rails and fastenings. It involves repeatedly returning to the same place to surface the track and add further ballast. It is, therefore, important that a permanent remedy be found. Poor drainage can also cause failures in the signalling system, where saturated ballast provides an alternative path for track circuit currents. This is called “sagging track”. Drainage systems are used to prevent run-off from adjoining land entering the track. They also provide for water falling on the track to get away so that the track is not flooded. Drains need to be maintained to make sure that they operate effectively. Blockages should be removed from drains. These may be caused by fallen rocks, sediment or loose soil in cuttings, and rubbish, old perway material, weeds and even ballast in cess drains and sub drains. The slope of drains may be altered by scouring, work around the track or vehicle access. Regular inspection of the track, especially during heavy rainfall, is essential to help identify potential problems. Remember that there are also drains at the top of cuttings that intercept water that would otherwise run down the cutting face. In pipe and sump drainage systems, keep outlets clean to allow water to flow, clean sumps regularly, make sure that sump covers and grates are in position and that grates are not blocked. Pipes may be broken by track activities or by vehicles being driven over them.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 147 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
It is good maintenance practice to clean and repair drainage systems before or during any major track activities (resurfacing, reconditioning, ballast cleaning etc). Poor drainage will lead to the early failure of improvement works. If there is any evidence of track formation, cutting or embankment failure, such as earth movement, track subsidence or ground cracks expert examination may be required to help identify geotechnical problems. More information on drainage repair and installation practices can be found in Engineering Manual TMC 421 – Track Drainage.
C11-7
Formation and earthworks
C11-7.1
Formation Track formation is the foundation on which the track structure sits. It is designed to: • Have sufficient strength to support the loads passed down from the rails through the sleepers and ballast. • Be impermeable to water and sloped that water will drain away from the track. Formation may fail if: • The loads imposed on it exceed its design strength, either because of increased axle loads or, more commonly, because of impact loads from poor geometry or degraded ballast. • It is weakened by water trapped in the earthworks or ballast by poor drainage. It is important to provide suitable drainage to preserve the stability of the formation. Water trapped in the formation can be removed by tapping the lowest level and providing suitable permanent outlet drains. Before deciding the actual method of treatment, the local conditions must be investigated. The objective of the investigation is to try and determine the source of the water and to obtain an outline of the water pocket. Expert advice from RailCorp’s Geotechnical Section will result in an appropriate design solution. The remedy will vary at different locations but will generally include excavation and removal of the water pocket and fouled ballast, establishment of horizontal drains at the base of the pocket leading to cess drainage and upgrading of drainage to prevent further water penetration.
C11-7.2
Earthworks Embankments support the formation. Embankments may fail if they are not properly drained. Cuttings, likewise, may fail if drainage is interrupted. Slips need not be large to cause serious damage and are very dangerous in that they can occur suddenly and without warning. They may be of several types: Flow movements The soil material of a hillside or embankment may become so thoroughly saturated with water that it moves downward in the form of a mud or sand flow. The rate of flow may be slow or rapid depending on the degree of saturation and type of material. The slopes from which the flow starts need not be steep if excess water is present. The effect of this type of slip is to cover the track or, push it out of line and destroy any form of support or
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 148 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
retaining wall. In embankments, the flow can remove ALL of the track support, leaving the rails and sleepers swinging in mid-air. Shear failure It sometimes happens that an embankment or hillside is composed of a soil without any great strength or cohesion between its particles. It may be standing too steeply or cracks may develop which will permit the entrance of water. Movement takes place slowly at first, but becomes very rapid as complete failure takes place. This type of slip may occur at any time, even many years after the railway is constructed. Slope adjustment: This is a natural occurrence due to erosion. Small quantities of spoil or rock fall away from the sides of cuttings and fall onto the track. They may be composed of fine material or rocks that are large enough to derail trains. Protection against the damage can be afforded by periodically removing any loose stones and by the provision of a wide bench at the toe of the cutting in which debris may collect clear of the track. Embankments may also be subject to erosion that will cut into the edge of the formation and undermine the track. Construction activities: Care is needed when construction activities are undertaken at the base of embankments and cuttings so that they don’t interfere with drainage or remove the toe, potentially destabilising the slope. Excavation often needs to be undertaken alongside or under the track. It is important that open excavations are properly shored to support the track without loss of track geometry and that the earthworks and formation are properly restored and compacted at the completion of the work. Settlement of restored earthworks in excavations leads to track geometry defects. More information on formation and earthworks repair and installation practices can be found in Engineering Manual TMC 403 – Track Reconditioning Guidelines and TMC 411 – Earthworks. Control and treatment of slips Terracing and flattening of slopes will assist in bringing about stable conditions. Cuttings, in soft material or in slopes liable to fall, may be widened to provide space for falling debris clear of the track. Small slips may be foreseen and prevented by the removal of loose material or the building of some form of protective structure. Mud flows, which result mainly from heavy rainfall, cannot be prevented and are not always foreseen. The removal of only the 'toe' of a slip will lead to increased sliding. No work should be undertaken that will remove material from the base of embankments or cuttings without a design approved by the Geotechnical Section.
C11-8
Turnouts Turnouts and other special trackwork behave in many ways similar to plain track. Ballast, bearers and fastenings rails and geometry are loaded in the same way, and their condition deteriorates in the same way. Maintenance requirements and methods are generally the same.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 149 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
There are, however, some significant differences in components, forces, deterioration and maintenance, due, principally, to the additional steelwork and special fastenings and the impact of degraded condition on the operation of the points. Turnouts are the only major track components that have moving parts. Turnouts are designed to switch trains travelling on one track on to another track. In addition to plain track requirements, turnouts must: • Provide a clear change in direction for all wheels of a train. • Make changes in direction uniformly and completely • Not obstruct the movement of trains in the chosen direction Well maintained turnouts demonstrate the following qualities: • Switch tips guide the wheels in the chosen direction. They will be shaped correctly, not blunt or damaged. The front of the switch will fit neatly against the stockrail in the closed position, and open the standard distance in the open position. Stockrails will not be worn or have rail flow that prevents the switch fitting neatly. • Switches do not open or move under load. The switch heel will be well packed so that it doesn’t pump, and the switch bearers will be level and provide adequate support. Switch stops will provide support for the closed switch. • There will be no obstructions to switch movement such as ballast or rubbish, nor will the points be difficult to operate because of switch or heel condition. • The stockrails and switches will be restrained from movement in hot and cold weather. Chairs and fastenings will be in good condition and firmly fastened to the stockrails • Crossings will provide a clear path for wheels to follow in the correct direction. They will not be blunt, broken or battered. Checkrails are installed to provide a guideway for wheels through the crossing. To be effective they must be securely fastened to the checkrail carrier and be maintained at the correct distance from the nose of the crossing. • Track geometry on both the through track and the turnout track will be good. Switches and stockrails When switch condition deteriorates it may have a damaged broken or blunt tip, it might not sit firmly against the stockrail, or it may ride higher than the stockrail. These conditions need to be corrected, either by grinding or by replacing the switch. Welding repairs cannot be undertaken in switches. Switches cannot be fastened like normal rail because they need to move. So that they don’t spread or roll under load, they are supported on flat switch plates, and by sitting against the stockrail near the front and switch stops extending from the web of the stockrail for the rest of the switch length. In tangential turnout designs now used in RailCorp, the switch is made from a special rail section that is shallower and thicker and is more resistant to rollover. When any of these components wear, become loose or fail, the support for the switch is degraded. The switch may open under load leading to a derailment when a wheel travels on the wrong road. Gauge widening and rail wear in stockrails should be corrected. Stockrail fastenings (chairs and bolts) need to be kept tight or replaced. Switch stops should be tight and be the right length. Stockrails are subject to the same longitudinal stresses in cold and hot weather as rail in plain track. Longitudinal rail movement in turnouts does not cause misalignments because of the greater resistance to lateral movement, but it might cause detection errors
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 150 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
in the signalling equipment connected to the points, resulting in signal failures. Stockrails in well maintained turnouts are securely fastened to the bearers with rail brace plates and chairs. If the chair bolts become loose or break, they must be tightened or replaced. Some turnouts have heeled switches. The condition of the heel joint is very significant to the satisfactory performance of the switch. If the heel is pumping the point of the switch will rise up under load. This could lead to a derailment. Pumping heels should be lifted and packed. If there is evidence that ballast or formation has failed then they will need to be replaced to achieve a permanent solution. Heels behave like mechanical joints and are subject to similar failure modes. They may become loose and foul, have battered and chipped ends and the bearers and fastenings may fail under the increased loading at the joint. Maintenance and replacement activities at heel joints are similar to mechanical joints. Crossings and checkrails At V crossings in turnouts (and V and K Crossings in diamonds) the two tracks cross each other and wheels need to be guided to maintain the right path. There is a gap in the wheel path at the crossing and checkrails are installed opposite the crossing to control the wheel set through the gap, so that the wheel lands on the correct side of the crossing. The noses of crossings get worn and battered under load. Crossings may be repaired by wirefeed welding. If this is not practical, either because there is too much damage or because the material can’t be welded (manganese and chrome vanadium crossings) the crossing will need to be replaced. The gauge, checkrail effectiveness and flangeway clearance are critical dimensions at crossings. They can be affected by wear of the crossing and checkrail or by loose or worn components. When dimensions vary from the allowed tolerances, the cause needs to be established so that the appropriate corrective action can be taken. The three dimensions are connected and correcting one may make the others exceed tolerances. Crossings are subject to heavy impact loads. Crossing bolts may work loose or break and the bearers, fastenings and ballast may fail under the increased loading. Where bolts become loose or break the must be tightened or replaced. Maintenance and replacement of bearers, fastenings and ballast are similar to these activities in plain track. Swingnose crossings are not subject to the same impact loads as crossings in standard turnouts. They do, however, behave like a switch and have similar failure modes. The condition and fit of the point of the crossing where it sits against the wing rail and the ease and security of movement in each direction are critical to the satisfactory operation of the swing nose mechanism. More information on turnout repair and installation practices can be found in Engineering Manual TMC 251 – Turnouts and Special Trackwork.
C11-9
Clearances and obstructions Trains need a clear space to operate in. Track infrastructure is designed to provide clearance between tracks so that trains don’t hit each other when passing, and to provide clearance to trackside structures such as overbridge piers, tunnels, OHW structures and signals, platforms and cuttings. Structures do not, generally, move but it can happen. Ballasted track can move. The maintenance effort is directed to regular checking of track centres and clearances. When the clearances degrade track geometry must be corrected or the structure moved.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 151 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Obstructions also interfere with clearances. Obstructions include trees or rocks falling from cuttings during wet or windy weather, slips in cuttings pushing material on to the track, ballast and perway material left on track foul of train trips, train stops and points, and rubbish and dead animals left or deposited on track. The maintenance effort in cuttings is mainly directed at prevention, by looking for and removing or securing vulnerable trees and rock, or by assessing and improving slope stability. Perway materials should not be left on track unless they are secure and clear of trains and signalling equipment. Loose material, even when left clear is a target for vandals.
C11-10
Right of way In general the Right of Way, which is the area of land either side of the tracks extending to the fence line, does not have a direct impact on the safe operation of trains. RailCorp is, however, a property owner and a neighbour, and has legal and moral obligations for the maintenance of its property. Fencing and gates are erected to restrict access. Fencing becomes ineffective when it is damaged or breached. Maintenance effort is directed at finding and fixing damage. Damaged or broken gates or missing locks are similarly ineffective and need to be repaired or replaced. Gates should never be left open. More information on fencing repair and installation practices can be found in Engineering Manual TMC 511 – Fencing. Firebreaks must be maintained on RailCorp property and fire hazards reduced prior to the bushfire season each year. In most areas this is achieved by mowing or slashing. Herbicide spraying is avoided if possible and can only be used under strict environmental controls. More information on hazard control practices can be found in Engineering Manual TMC 501 – Bushfire Hazard Management. Vegetation that interferes with clearances or restricts sighting distances at signals and level crossings should be removed. RailCorp has an obligation to control noxious plants on its property. Access roads are constructed to make infrastructure maintenance easier by giving ready access to and alongside the track. They also provide access to emergency personnel when an accident has occurred. They need to be kept in passable condition. The maintenance effort should be directed at maintaining surface condition, drainage, repair of erosion and scours, clearing and repair of under-road pipes and culverts and removal of vegetation blocking the roadway.
C11-11
Housekeeping Material left at worksites after a job gets forgotten. It could be buried in a pile of old ballast or fill, left on track to be buried in the ballast during resurfacing, or laid on the right of way and covered with weeds and grass. Left like this it becomes an obstruction for drainage, for work on the Right of Way or a safety hazard for track workers. It also provides material for vandals.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 152 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
When work is finished it is good practice to remove any unused or redundant material from site. Some can be reused. If it can’t be taken off site immediately it should be stacked and secured in a marked storage area for later retrieval.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 153 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Chapter 12 Ballast reconditioning methods When ballast becomes fouled with mud and degraded ballast material, it loses its ability provide drainage of water through the ballast down to the formation and into the drainage systems. The trapped water weakens the formation, resulting in soil from the formation rising in the formation and causing pumping track. Pumping track, in turn, affects track geometry and track stability. Ballast condition can only be improved by ballast cleaning or replacement. Methods of ballast reconditioning include:
C12-1
Manual reconditioning In manual reconditioning, ballast is broken up and shovelled manually from the track. Fresh ballast is shovelled in to restore ballast profile. Manual lifting and levelling is required to restore the correct track geometry. This is a very slow method, labour intensive and usually only used for very small areas. A variation of this method is to use machinery to dig out all the foul ballast and replace it from an on-site stockpile of new ballast.
C12-2
Ballast cleaning In ballast cleaning the existing ballast is removed from the track, it is sieved, any foreign material and improper size material is removed and any acceptable material is returned to the track. This work is carried out using ballast cleaning machines. A ballast cleaner is basically a rail mounted vehicle and power unit. On the vehicle there is mounted a large triangular guide frame. The two 'sides' of the triangle consist of two troughs that run up, along each side of the machine. The 'base' of the triangle is formed by the assembly of the detachable 'cutter bar' unit. The 'cutter bar' is assembled under the track in an excavated trench. It is then joined to each side of the machine to form a guide for the 'Continuous Cutting Chain'. As the cutting chain rotates it excavates the ballast from beneath the track. Excavated ballast is carried up the ascending trough on the machine where it is dropped onto vibrating screens. On these vibrating screens the ballast is broken up. Undesirable large stones are diverted away via the top screen and 'fines' pass right the way through where they also are diverted. The large stones and fines are then discarded by way of conveyor belts, on to an adjacent embankment or into a special spoil train for removal. Any acceptable ballast is returned, clean, to the track. Advantages • • • •
© Rail Corporation Issued June 2012
The track is not lifted. We can lower the track if required. Most foul ballast is removed. Resleepering is made easy due to skeletonised track. Minimal manpower. Longer areas can be upgraded in a relatively short time.
UNCONTROLLED WHEN PRINTED
Page 154 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Disadvantages • Does not fix capping layer or formation failure.
Figure 235 - Ballast Cleaner in action
Figure 236 – Cutter bar and chain
C12-3
Track reconditioning In track reconditioning a section of track is cut out and removed with off-track plant. track plant then dig out the foul ballast and formation. The formation, drainage capping layer are reconstructed and ballast laid on top. The track is then replaced more ballast dropped so the resurfacing team can restore the correct track geometry ballast profile.
Offand and and
This method is usually used when there is a formation or capping layer failure thus causing the ballast to become “foul”.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 155 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
This method is widely used and is very effective as we can recondition the formation, capping layer, ballast, sleepers, and drainage all in the one operation. Sometimes a geosynthetic is laid to assist the capping layer in diverting water and dirt from the formation. Advantages • • • • •
Very effective on small areas Excellent end results. Formation, capping layer, ballast and drainage upgrade. Can be carried out in any area. Limited manpower. All foul materials removed.
Disadvantage • Very high cost for a relatively small area upgraded.
Figure 237 – Track reconditioning
Figure 238 – Geosynthetics – Geogrid (L) and Geofabric (R)
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 156 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Chapter 13 Resleepering When timber sleepers become termite infested or rotten, or when they are crushed, broken, split or cracked they cannot support the load from the rails, nor can they support the fastenings. These sleepers need to be replaced. Sleeper replacement is undertaken using the following methods.
C13-1
Manual resleepering Sleepers can be removed by hand using basic fettling tools including “pigs foot”, spiking hammer and claw bar. This method is suitable for use with timber sleepers only because of the weight of concrete sleepers. In recent years, off track machines (backhoes and bobcats) with specialised attachments have been used to reduce the manual labour required and allow a much more efficient process. Replacement of individual concrete sleepers can be undertaken with this machinery.
C13-2
Mechanised resleepering Mechanised sleeper renewal is carried out by a dedicated team using on and off track machines. Machinery includes: • • • • • •
Spike removers or elastic fastening removers. Tie handlers and Track Jacks. Ballast bed scarifiers. Spike drivers or elastic fastening applicators. Tie tampers and Ballast regulators. Bob Cats, Backhoes and Excavators.
Each machine has a specific part to play in the process.
Figure 239 - Mechanical removal of sleepers
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 157 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Figure 240 - Fastclip remover
Figure 241 - Transporting sleepers with on-track pettibone
C13-3
Track laying machine The track laying machine (TLM) can renew both rails and sleepers in one operation and is usually used to upgrade the track from timber to concrete sleepers. The TLM operates in two modes: Construction mode – with no track in front of the machine, the front bogie is replaced by caterpillar tracks. As it moves forward the TLM lays concrete sleepers on the ballast and threads rail onto the sleepers. The rear bogies of the TLM and its support wagons travel on the newly laid track. Relaying mode – the front bogie of the TLM runs on the old timber track. In the centre of the machine the old timber sleepers are picked up and the new concrete sleepers are laid. Rail is threaded onto the sleepers and the rear bogies of the TLM and its support wagons travel on the newly laid track.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 158 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Figure 242 – Track laying machine (TLM)
Figure 243 – Caterpillar tracks on front of TLM
Figure 244 – Rails threaded around the TLM
© Rail Corporation Issued June 2012
Figure 245 – Laying sleepers
UNCONTROLLED WHEN PRINTED
Page 159 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Figure 246 – Threading rail back onto new sleepers
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 160 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Chapter 14 Maintaining Track Geometry Poor track geometry displays changes in top, line, twist or superelevation that could cause passenger discomfort, increased impact loads, incorrect rail adjustment, incorrect track centres and structure clearances or, in extreme circumstances, derailments. Correcting track geometry is an on-going maintenance task. include:
C14-1
Activities and methods
Maintaining track alignment and line The term “Lining the track” means to repair/restore the horizontal or lateral position of the track. Line is normally programmed for repair by resurfacing machines but can be carried out manually when required using bars and manpower or large off track machinery to move the track.
C14-2
Lifting and levelling The term “Lifting and Levelling” means to correct errors in rail level and cross level in the track (vertical movement). Resurfacing machines are normally programmed to repair any major deficiencies in track geometry but the work can be carried out manually. Hydraulic jacks, shovels and beater packers or mechanical tampers are used to lift and pack track manually.
C14-3
Resurfacing Resurfacing is the process of lifting and lining the track with special machines to restore the correct track geometry, carried out by specialist teams. The role of the resurfacing team is to restore the track geometry to meet the relevant Technical Standards for track construction or maintenance. This work is carried out as part of major renewal projects or as part of the regular maintenance cycle. Specified tolerances are set out in the Engineering Manual TMC 211 for the following: • • • • • •
Track alignment in relation to survey. Rail level in relation to survey. Superelevation and cross-level. Overhead clearances (bridges, wiring etc). Trackside clearances (platforms, structures etc). Ballast profiles.
Resurfacing may be carried out in different “modes” depending on local requirements and can range from a simple “smooth” resurfacing job to design resurfacing.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 161 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
C14-3.1
TMC 202
Smooth lifting/lining This process is used when there is inadequate survey information. The tamping/lining machine is set up as normal and only a basic lift is applied in order to smooth out the irregularities in the track geometry. Cross level errors are corrected as are the superelevation ramps. Errors in rail level and alignment errors are not eliminated as no reference to survey is made. Errors in longitudinal rail level (top) can be eliminated in this process by the use of optic levelling equipment to determine lift values between high points and then applying these values at the front of the machine. This process should result in smooth top and line, irrespective of survey.
C14-3.2
Design lifting/lining This process is used when full survey information is available to enable the team to put the track on correct alignment and height. It involves the team’s ground staff continually moving ahead of the machines, measuring the track in relation to the survey information. The differences in height and alignment are marked so the front tower operator can make the necessary adjustments to the machine in order to achieve the desired lifts and slews. Resurfacing teams are supplied with the equipment to take the necessary measurements. They must also be supplied with “G” sheets or similar which show; curve kilometrage, radius and direction, location of tangent points and transition points, superelevation and ramp length etc. Apart from measuring and marking the track ahead of the machine, the ground staff must also identify and mark all immovable rail level obstacles so they can be clearly seen by the operators in order to avoid damage to the machine or track structure. Some of these obstacles include: train stops, impedance bonds, signal wires, guard rails, level crossings, interlocking gear etc.
C14-4
Machine types The machines that make up RailCorp’s fleet are self propelled, diesel powered on-track units. The types of machines include track tamper/liners, ballast regulators and dynamic track stabilisers.
C14-4.1
Tamper liners Tamper liners are lifting, levelling and lining machines. The lifting system uses a static wire as a reference point above and parallel to the desired rail level. These wires, through the use of electrical measuring units, detect and measure longitudinal rail deflections. An electric pendulum measures the cross level. These measuring units (called potentiometers) activate the lifting mechanism, then, by the use of hydraulic cylinders, the rails are lifted until any errors are eliminated, at which time the lift automatically cuts out and the track held at that level until the packing of the sleepers (tamping) is achieved. The maximum effective lift that can be achieved in one tamping pass is 50mm. Tamping is achieved by a series of vibrating flat faced tamping tools being pushed towards each other below sleeper level by hydraulic cylinders, to compact the ballast.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 162 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
To tamp a sleeper successfully, the following must apply: 1.
There must be enough ballast to achieve minimum ballast profiles after the lift.
2.
The ballast must not be heavily cemented, (unable to flow).
3.
The tamping tools must be of correct dimensions.
4.
The tamping tool must go to correct depth.
5.
Vibration speed must be maintained at approx. 35 cycles/second (-2100 rpm.)
6.
Squeeze pressure must be adequate but not excessive.
7.
For consistency, time of tamping must be consistent.
8.
The sleeper being tamped must be sound (not rotten or hollow).
These machines are also fitted with a single chord lining system which operates on the same principle as the lifting system, however on a horizontal plane not vertical. Depending on the type of machine and the track conditions, the maximum slew may range from 50mm to 150mm in one pass.
C14-4.2
Ballast Regulators Ballast regulators are used to shift ballast for a number of reasons:
C14-4.3
1.
To bring in enough ballast for the tamper to work with.
2.
To clear the rail head and allow identification of sleepers for the tamper operator.
3.
To fill the cribs to prevent ballast put under the sleeper by the tamper from moving out.
4.
To place surplus ballast on the shoulders after tamping.
5.
To broom ballast away from rails and fastenings for inspections and to allow timber sleepers to dry out.
Dynamic Track Stabiliser After tamping has occurred the process of consolidation takes place over a period of time due to the amount of traffic that has passed over the tamped areas. The Dynamic Track Stabiliser can consolidate the tamped area in one pass by vibrating the rails and ties and applying downward pressure to improve lateral stability as fast as possible in a controlled manner. Conditions required for effective stabilising of the track include:
© Rail Corporation Issued June 2012
1.
Ballast must be relatively clean and free flowing (i.e. not heavily fouled).
2.
Ballast should preferably be regulated to fill cribs and form shoulders before stabilising.
3.
Ballast must have been disturbed i.e. ballast cleaned and /or tamped.
UNCONTROLLED WHEN PRINTED
Page 163 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
4.
C14-5
TMC 202
Rail to sleeper fastenings must be sound to transmit horizontal oscillation generated by the machine through the rails into the sleeper and, consequently, the ballast.
Preliminary work Before any resurfacing work can be carried out, there is much preliminary work that should be undertaken. Some of the more important areas requiring attention include:
C14-5.1
Drainage Any attention to drainage systems should be completed prior to resurfacing. The importance of effective drainage in providing stable track was explained earlier. Any areas of suspect drainage should be attended to as a matter of urgency if the resurfacing is to realise its full value.
C14-5.2
Sleepers PRS work should be completed prior to resurfacing. Any resleepering after the track has been resurfaced will disturb the track and possibly re-introduce “top” and “line” defects back into the track. Also, during resurfacing the machinery relies on the rail being securely fastened to the sleepers. As the machine lifts the rail to the correct level, the sleeper must also rise to allow for correct packing of the ballast beneath it. Any sleepers that do not rise up will not allow the machine to correctly pack the ballast. Therefore, any defective or ineffective sleepers should be renewed beforehand if resurfacing is to be worthwhile.
C14-5.3
Ballast Careful consideration must be given to the amount of ballast available on site. As resurfacing involves the lifting of the track, enough ballast must be in place prior to work commencing to allow for the correct ballast profile at the completion of work. As a “rule of thumb” about 3 to 4 tonnes of ballast should be run out per 20m of track to be resurfaced.
C14-5.4
Survey information To allow the resurfacing team to achieve the best possible results, accurate survey information must be available. Any necessary survey work must be completed prior to resurfacing. In any case, special attention must be given to locating tangent points, transition points, compound tangent points and changes in superelevation.
C14-5.5
Amount of lift The amount of lift required to restore the track must also be considered. • Will clearances be affected? • How far above the monument/plaques is the track already?
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 164 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
• What about overhead wiring?
C14-5.6
Obstructions Any potential obstructions to the resurfacing operation must also be removed prior to commencement. Some of these obstructions include: • • • •
Rail lubricators. Guard rails. Board walks. Level crossings etc.
Joint pre-work inspections by Local Officers and Resurfacing Managers should be made to ensure the resurfacing sites are prepared and ensure a more productive operation.
C14-6
Identify any other associated work needed Each proposed tamping kilometrage should be inspected to identify any work needed to effectively tamp the location. Tamping is most effective where: • • • • •
Track can tolerate a vertical lift of at least 20mm. Tie fastenings are secure. At least 150 mm of clean ballast is available below the ties. Sufficient ballast is available for filling tie cribs and making up shoulders. All tamping obstructions are removed. (If obstructions cannot be removed they must be marked and protected from possible damage).
Moreover, existing conditions determine the modes of operation that can be selected for tamping, and therefore, the quality of finish that can be expected.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 165 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Chapter 15 Rail Adjustment Fundamentals C15-1
Introduction This chapter provides an introduction to rail adjustment and track stability as a basis for adjustment processes described in detail in other manuals. It includes information on: • Temperature effects in rails leading to compressive and tensile stresses. • Control of expansion and contraction in rails. • Maintenance of track stability and the role of track components in track stability. Since rail adjustment is a principal consideration in the maintenance of track stability in hot weather, information is also provided on the prevention of misalignments including Welded Track Stability, Work in Summer Months and WOLO speed restrictions.
C15-2
What is a misalignment? A misalignment, also commonly referred to as a `buckle’, is a short, sharp sideways movement of track. It can result in either a sharp radius curve or an `S’ shape. The resulting track geometry cannot usually be travelled over by a train at speed, and in many circumstances is too sharp for any train movement. The degree of hazard depends on the size of the lateral displacement and the distance over which it occurs, and on the train speed.
Figure 247 – Misalignment on a curve
Figure 248 – ‘S’ shaped misalignment on tangent track
Figure 249 – Small misalignment on a curve © Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 166 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
C15-3
TMC 202
What causes a misalignment? Railway track is dynamic. Rails are subject to thermal stresses as temperatures increase or decrease and will go into compression or tension, respectively, as the temperature varies from the neutral temperature at which the rail was installed. When the compressive forces in the rail exceed a certain stress level, the rail will buckle unless it is restrained.
C15-4
Temperature effects in rails Rails expand and contract (get longer or shorter) as the rail temperature increases or decreases. When rails are free to move they will expand and contract 0.115mm for every 1m in length for every 10°C change in rail temperature. For example a 110m length of rail will get 12.65mm longer when the rail temperature increases 10°C. The rail will get shorter by the same amount if the rail temperature decreases 10°C. An unrestrained 110m rail would grow 19mm if the rail temperature increases from 20°C to 35°C. When rails are laid in track they cannot expand or contract this amount, because they have been welded to other rails or connected with fishplated joints. In the case of track with jointed rails, the potential for free movement is only 13mm, which is the gap at each joint. In continuous welded rail there is no potential for free movement because there are no joints.
C15-4.1
Stress If the rail cannot expand or contract, stress is created in the rail. There are two types of stress:
C15-4.2
Compression
As rails expand with heat, any free movement is taken up. When there is no more movement left a force is built up in the rail by expansion. This is called compression.
Tension
When the rails cool any free movement is taken up by contraction. When all movement is taken up, and the rails continue to contract, a force is built up in the rails. This force is called tension.
Effects of compression When rail is in compression it tries to relieve the compressive stress by getting longer. It will try to move sideways to get longer. Compression (stress) is normal and can be contained within the track structure under normal conditions i.e. when the track structure is to standard. The track structure (the assembly of rails, fastenings, sleepers and ballast) is designed to resist a certain amount of sideways thrust that comes from the compressive stress in the rails. When, however, the amount of compression generated in the rails exceeds the ability of the structure to hold itself in place, track movement occurs. This movement is known as a misalignment (or buckle).
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 167 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Figure 250 - Misalignment
C15-4.3
Effects of tension On curved track, tension may have a similar, but less dramatic effect on the track. When rail is in tension it tries to relieve the compressive stress by getting shorter. It will try to move sideways to get shorter. Tension (stress) is normal and can be contained within the track structure under normal conditions i.e. when the track structure is to standard. If the amount of tension generated in the rails is greater than the resistance offered by the track structure, the curve will tend to pull in towards its centre.
Figure 251 – Curve pull-in This track movement is less dramatic than a misalignment because the track movement occurs over a much longer distance. The movement may not be obvious but it can be extremely dangerous when clearances are affected. Other indications of excessive tension in rails are broken rails, bent or broken bolts, or breakaways as the rails pull apart. The adjustment of rails, therefore, is a most necessary and essential part in effective track maintenance. Rails, ballast, ties, fastenings and rail adjustment all interact to provide a stable track structure.
C15-5
Control of expansion and contraction Rails experience both cold and very hot temperatures in track and will, therefore, experience both expansion and contraction or compressive and tensile stresses. These stresses are controlled by: • Establishing and maintaining correct rail adjustment. • Providing and maintaining lateral resistance to movement. • Controlling the additional forces that can initiate misalignments or pull-ins.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 168 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
C15-5.1
TMC 202
Establishing rail adjustment Rails have to be adjusted so that they don’t generate excessive compression or tension. The adjustment is carried out by ensuring that each rail will be stress free (no compression or tension) at 35°C rail temperature. This is called the “Neutral temperature”. The temperature has been specially selected for rails in RailCorp infrastructure and is a balance between the extremes of heat and cold experienced in the Railcorp system. If rails anywhere in the system have been correctly adjusted to the Neutral Temperature, the normal range of operating temperatures will not generate excessive compression or tension. In CWR the rails will always be compression when the rail temperature is over 35°C, if the rails are correctly adjusted. When the rail temperature is under 35°C correctly adjusted CWR will always be tension. Jointed rails will be in compression if the joints are closed up to zero. What rail temperature this occurs at depends on the length of the rail. For example correctly adjusted 110m rails will be in compression at 40°C rail temperature. Shorter 13.72m rails, however, do not go into compression till the rail temperature reaches 75°C Likewise, rails will be in tension if the joints are fully open to 13mm. Again, the rail temperature this occurs at depends on the length of the rail. For example correctly adjusted 110m rails will be in tension at 29°C rail temperature. Shorter 13.72m rails however do not go into tension till the rail temperature reaches -11°C.
C15-5.2
Maintaining rail adjustment
C15-5.2.1
Rail creep Rails in service are subject to longitudinal forces from: • The braking action of the trains pushing the track in the direction of travel. • The acceleration of the trains pulling the rail in the opposite direction of travel. • Wave motion caused in the rails by the passage of the train wheels. This will push the rails in the direction of travel. These forces can result in the rails moving. If the rails move longitudinally the rail adjustment will be affected irrespective of the type of rail (Jointed Rail or CWR). To illustrate this point, consider an example where jointed track is on a steep grade. If traffic continually runs downhill, the rails will tend to run downhill as well. This will result in wider rail gaps at the top of the grade and narrower gaps toward the bottom, with the result that there will be too little steel at the top of the hill and too much steel at the bottom. Continuously welded rails behave in the same way; steel will bunch up in one location and be stretched at another, altering adjustment. Standard track consisting of formation, ballast, ties, fastenings and rail is designed to interact to resist the longitudinal movement of rail.
C15-5.2.2
Ballast As well as providing a flexible base for the track, transmitting axle loads to the formation, and providing the vertical and lateral support to the sleepers to maintain track geometry, ballast provides resistance to the longitudinal and lateral movement of sleepers.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 169 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
The angular shape of the ballast serves to lock the sleepers in place. (Evidence of this can be seen in the marks on the underside of a sleeper that has been removed from the track). In order to do its job effectively, ballast must have the following qualities:
C15-5.2.3
Grading –
Specified shape and size (see TMC 241 - Ballast) to effectively lock together. Poorly rounded or graded ballast will not provide the designed resistance to movement.
Cleanliness –
Ballast that contains fine contamination, weeds etc will not provide effective interlocking or resistance to sleeper movement.
Profile –
Specified profile (see TMC 241 - Ballast). Ballast deficiencies will significantly reduce resistance to sleeper movement.
Sleepers In addition to holding the rails to gauge and transmitting the axle loads from the rails to the ballast, sleepers provide resistance to longitudinal movement of the track by holding the rails in position through the fastenings and by engaging the sharp faces of the ballast. Sleepers that are broken, cracked, split, crushed or rotten will not be effective.
C15-5.2.4
Fastenings Fastenings are used to connect rails together (fishplates and bolts), tie the rails to the sleepers (spikes, clips and sleeper plates) and to restrict longitudinal movement of rails relative to the sleepers (anchors and resilient fastenings). Anchors are installed to prevent longitudinal rail movement (creep) and to evenly distribute stresses along the full rail length. Without rail anchors in jointed rail the majority of stress would occur at the ends of the rails. In CWR the stress will occur at fixed points (e.g. turnouts). By holding the rail in place with rail anchors these stresses are spread out over the whole length of the track. To achieve effective anchoring the following points must be remembered: • Maintain the standard anchor pattern. (i.e. box anchor every second sleepers for 32 ties at mechanical joints and box anchor every fourth tie along the rail). Standard anchor patterns are detailed in TMC 221 Rail Installation & Repair. Additional anchors are sometimes installed to control creep on steep grades. • Make sure the anchors fit hard against the sleeper. • Make sure the anchors are not overdriven. Overdriving anchors will ‘spring’ them (destroy spring action) and make them ineffective. • Monitor rail creep by punch marking rails in relation to fixed points. For effective anchoring with resilient fastenings: • Do not overdrive clips. • Replace any “sprung” clips.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 170 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
C15-6
TMC 202
Providing and maintaining lateral resistance The standard track structure of formation, ballast, ties, fastenings and rail as previously described is also designed to interact to provide a structure that resists the lateral forces generated by compressive or tensile forces in the rail. This is achieved by • Anchors & fastenings or resilient fastenings being properly installed and effective in providing a ladder track structure • Good sleepers, firmly fastened to the rails and firmly bedded to the ballast • A full profile of good clean draining, firmly compacted ballast Overall the contribution of each component in the track to track stability is as follows: The degree of RESISTANCE is provided by • Rails • Fastenings • Sleepers and Ballast
approx. 10% approx. 30% approx. 60%
60% of the RESISTANCE to BUCKLING is given by the SLEEPER in the BALLAST. • Bottom of tie • Sides of the tie • Shoulder Ballast
C15-7
approx. 25% approx. 25% (Full Crib) approx. 10%
Maintenance of Track Stability High temperature is NOT the cause of misalignments. Properly constructed and maintained track will not misalign in the normal range of temperatures experienced in RailCorp. The most common causes are
© Rail Corporation Issued June 2012
1.
Track not correctly adjusted to be stress free at 350C.
2.
Loss of rail adjustment due to uncorrected rail creep or addition of steel when repairing rail defects or renewing rail.
3.
Frozen joints or rail end flow at joints – restricting expansion or contraction.
4.
Uneven stresses occurring in track due to fixed or bunching points eg at level crossings, turnouts, welds binding on sleeper/plates, patches of resilient fastenings in dogspiked track, anchor points left in track, twisted sleepers/sleeper plates, angle fishplates with dogspike holes, fishplates “running” into dogspikes.
UNCONTROLLED WHEN PRINTED
Page 171 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Figure 252 – Local bunching point - weld is caught against sleeper - rail cannot move - sleeper will generally move with rail 5.
Figure 253 – These anchors aren't doing anything
Loss of resistance to lateral movement due to inadequate ballast profile or loss of frictional grip between ballast and sleeper. Loss of ballast grip is generally caused by track disturbance, by doing work on the track that breaks the bond.
Figure 254 – Ballast deficiency at a bunching point 6.
Trackwork initiators include resurfacing, rerailing, resleepering, ballast cleaning, earthworks and drainage, welding & CWR, trenching or installing cables under or alongside the track, repairing rail defects, damaging ballast shoulder/profile with plant/road vehicles or by repeated walking down the ballast shoulder.
7.
Track geometry initiators that create increased lateral force when trains pass over them. In the right circumstances these additional forces will break the bond between sleeper and ballast and trigger a misalignment. Geometry initiators include loose or flogging joints, pumping track, poor geometry such as poor top, poor line, especially ‘kinks’ or sharp spots in curves, bad weld alignment, both horizontal (line) and vertical (dipped), welding closures not crowed in curves, welding closure not matching rail profile either side eg curve worn rail, insufficient superelevation on curves
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 172 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
8.
TMC 202
Figure 255 – Pumping track
Figure 256 – Poor geometry
Figure 257 – Battered joint
Figure 258 – Loose joint
Rolling stock initiators including trains going too fast, overloaded or defective rolling stock, trains accelerating away from stations, trains braking – coming into stations and down steep grades, train loadings predominantly in one direction.
It is important to note that misalignments will occur at the weakest point. This may only be a short isolated piece of track in an otherwise very stable section.
C15-8
Prevention of misalignments RailCorp has established a number of systems and practices that if used correctly and in combination prevent misalignments occurring in the hotter months of the year. These are: • • • •
C15-8.1
Welded Track Stability Analysis – WTSA. Control of rail adjustment. Summer work practices. WOLO - heat speeds and inspections.
Welded Track Stability Analysis – WTSA To provide assurance that the design conditions are maintained during the summer period, track stability examination, analysis and correction are conducted between August and October each year.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 173 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
This involves inspection of rail adjustment, ballast profile and condition, fastening condition and areas of potential concern, analysis of contribution of these factors to the overall stability, and programmed, prioritised improvement at identified locations. The operation of the WTSA system is detailed in Engineering Manual TMC 203 - Track Inspection.
C15-8.2
Control of adjustment WTSA relies heavily on control of rail adjustment. In CWR, creep pegs are used to monitor changes. If uncontrolled rail welding occurs, adjustment control is LOST. If unreported, the loss of control is INVISIBLE. It is essential that all rail welding activities are properly controlled and reported. This is particularly important in colder weather, when uncontrolled rail welding will add steel. The methods of adjusting track, and of undertaking work on track without losing control of adjustment, are detailed in Engineering Manual TMC 223 Rail Adjustment. At any time (not just in the hotter weather) the following actions are required to control rail adjustment. • Extreme care is required whenever rails are cut, to ensure that STEEL IN = STEEL OUT. • If control is lost in CWR, the 500m section of track BETWEEN CREEP MARKS should be re-adjusted and re-punched. • Use double creep marks when re-punching. • Extra care is needed when cutting or laying rails at night, as misalignments can occur the next day if too much steel has been added. • When tamping curves, ensure that alignment is restored to the survey/offsets agreed with the Civil Maintenance Engineer.
C15-8.3
Work in Summer Months Restrictions on work affecting the track during the hotter months are provided in Engineering Manual TMC 211 Track Geometry & Stability. Engineering Manual TMC 211 establishes requirements for pre-season special spot inspections, special inspections throughout the summer and procedures for work in summer months. It also describes the DO'S and DON'TS of track maintenance in hot weather and provides guidelines for the issue of special instructions for work in Summer months. Civil Maintenance Engineers may authorize work in Summer by the issue of written instructions which will detail the special actions to be taken prior to, during and after the work to maintain track stability. In the absence of written authorisation from the Civil Maintenance Engineer, the "safety net" "Work in Summer Months" restrictions apply. These are detailed in Engineering Manual TMC 211. These instructions have also been reproduced on plastic card to be distributed to and carried by all Team Leaders, or staff acting as Team Leaders during the summer season. It is very important that everyone working on or near the track is aware of and understands special precautions that need to be taken to avoid track buckles
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 174 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Before you do any work that will affect track stability, you must check Engineering Manual TMC 203. • What is the current stability loss at the location? • When you do the work, what will the stability loss be when you've finished? • What actions are you taking to make sure the track won't buckle after the work is done? Remember it will take some time for the track to bed down again. Remember - the ballast shoulder should be at least 400mm wide, level with tops of sleepers. ALL staff when working on or near the track must beware of: • Bumping the track e.g. with earthmoving plant. • Knocking down or removing ballast profile e.g. with trucks or earthmoving equipment running along the ballast shoulder or climbing up the ballast shoulder. • Undermining the ballast profile by excavation e.g. excavation under or alongside the track for signals cables or services.
C15-8.4
WOLO - heat speeds and inspections When the AIR temperature on any day reaches or exceeds 38°C OR is predicted to reach or exceed 38°C the speed of trains is reduced in the hottest part of the day by imposing a WOLO speed. Reducing the speed of trains reduces the possibility of misalignments caused by trains and reduces the consequences if a train derails on a misalignment. The level of speed restriction and the procedure for applying it are detailed in Engineering Manual TMC 211 Track Geometry & Stability. In addition to WOLO speeds, when the AIR temperature reaches or is forecast to reach 38°C all welded track is inspected in the hottest part of the day for the purpose of detecting signs of misaligned tracks. This requirement is detailed in Engineering Manual TMC 203 Track Inspection. Engineering Manual TMC 211 Track Geometry & Stability provides further guidance on causes of misalignments and techniques for avoiding misalignments.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 175 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Chapter 16 Irregularities Basically, an irregularity is anything that affects the progress of a train. There are many different types of irregularities that affect the track. This chapter deals with some of the major types of irregularities. Your first obligation on finding an obstruction, or any emergency situation, is to protect the site from any other approaching trains. Once the site is protected, you should report the obstruction. Before you can report any irregularity that you find on or around the tracks, you must be able to report exactly where it is. You must be able to report the exact location of any irregularity. The location is always identified by the kilometrage, on whichever line you are on, plus the section that you are in. For example, "76.850km on the Main West in the Warrimoo - Valley Heights Section".
C16-1
Derailments and collisions Derailments and collisions are the greatest safety hazard in any rail system. Derailments can be caused by: • Train faults such as broken wheels and axles, poorly performing bogies or worn wheels. • Track defects such as twist, poor line, wide gauge or spread road. • A combination of train and track defects. • Misalignments and broken rails, washaways, slips and obstructions. Collisions can be caused by: • Misalignments and curve pull-ins when track centres are brought closer together or tracks are moved closer to structures or platforms, • Derailments where the derailed train ends up foul of trains on other tracks. Track Inspection and Maintenance practice is aimed at preventing derailments and collisions.
Figure 259 – Country derailments causing significant damage
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 176 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
C16-2
TMC 202
Figure 260 - Collision between a ballast train and an Xplorer
Figure 261 - Collision between a Coal Train and a Passenger train
Figure 262 – Derailment on a Misalignment
Figure 263 Collision with a platform after a derailment
Misalignments and pull-ins Misalignments are usually found in hot weather. Misalignments are caused by the rails expanding when they are heated. Because they are made in long, continuous lengths there is no room for them to expand as they get hotter. This causes them to "kick sideways" and cause a misalignment. In cold weather curve pull-ins are caused by the track contracting, causing it to pull out of line. This could cause problems with trains hitting station copings, other structures or other trains. Both these problems can cause severe ride quality problems, or even damage, to a train. If they are severe, they can cause a derailment.
C16-3
Breakaways & Broken Rails Breakaways occur when rails cool and contract. If they contract too much the joints between the rail ends are stretched. This causes the bolts to shear off or the bolt holes to fracture. The end result is that the gaps between the rails becomes much too wide, causing rough riding and the possibility of train derailment, as well as further damage to the rail.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 177 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Broken rails occur when there is a structural fault in the rails. The fault eventually fractures when the rail is put under tension due to cooling. Again, this can cause rough riding and possible derailment.
C16-4
Washaways
C16-4.1
Description During heavy and prolonged rain, the normal drainage channels provided may not be able to deal with the extra water flowing through them, with the result that flooding occurs. In flat country, embankments may become submerged and saturated. If the water level rises uniformly on both sides of the bank, there will not be a great amount of water flow. As a result, little damage will occur. If, however, the flooding is confined to one side of the line, bridge and culvert openings will be liable to scour. Should the water run over the top of the track, very serious damage can result. The amount of damage will be dependent on the velocity or rate of flow of the water. Any steps taken to reduce the rate of flow will, therefore, assist in reducing the damage. The danger point is reached as water first commences to trickle over the formation. Scouring then starts, first in the ballast and then in the formation. If there is a large difference in the water levels on the two sides of the bank, the rate of flow will be high and damage extensive.
Figure 264 - Flooding
Figure 265 - Washaway
Figure 266 – Washaway
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 178 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
C16-4.2
TMC 202
Treatment During heavy flooding, washaways may be numerous. They may range from small sections of ballast washed away to deep cuts where the whole embankment has been removed. The method of making temporary repairs will depend on the nature and size of the washaway and also the materials and equipment available. If the ballast only is scoured out, and it is not possible to get ballast to the site, quick repairs may be made by redistributing the remaining ballast. This will lower the track into a long 'slack' and is only a temporary measure to restore traffic. More permanent repairs must be completed as soon as possible. Ballast bags may be stacked under sleepers to support the track until additional ballast can be supplied. In this method degradable bags (hessian or similar) are partly filled with ballast and placed under the sleeper (under the rail). When additional ballast is laid the bags will eventually rot away leaving uniform ballast. Where shallow scouring of the formation occurs, temporary repairs can be made by lifting the track and flooding it with ballast, or by laying continuous sleeper pigsties. For deeper scouring, pigsties, trestles and temporary beams will be required.
Figure 267 – Washaway with sleeper pigsties being installed
Figure 269 – Washaway with sleeper pigsties installed
© Rail Corporation Issued June 2012
Figure 268 – Washaway with sleeper pigsties being installed
Figure 270 – Washaway with sleeper pigsties installed
UNCONTROLLED WHEN PRINTED
Page 179 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Figure 271 – Washaway with sleeper pigsties installed
C16-5
Figure 272 – Washaway with sleeper pigsties installed
Obstructions Obstructions can come in many forms, such as vehicles, trees, people, stock, old sleepers, carriage seats, land slides, rocks, etc. All of these things can cause damage and/or delays to a train.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 180 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
Chapter 17 Speed Restrictions Speed restrictions are placed on the running lines for the safe passage of rail traffic during track and bridge repairs or, where due to the condition or geometry of the track, rail traffic is unable to travel at normal speeds. Details for the different types of speed signs and procedures for imposing and removing speed restrictions can be found in the Network Rules and Procedures and in Engineering Manual TMC 211 – Track Geometry & Stability.
C17-1
Permanent speeds
C17-1.1
Permanent speed signs Permanent speed signs are placed on main lines and are necessary at various locations to advise train drivers of the maximum speed on the track ahead. Speed signs are placed on the left side of the track in the direction of travel. Permanent Speed signs are provided where: 1.
The speed through curves is reduced because of the geometry design.
2.
The speed to be travelled on the turnout road of a turnout needs to be advertised to drivers.
There are two different types of permanent speed boards: 1.
Black text on a white background for XPT, Xplorer and Endeavour trains.
2.
Black text on a yellow background for all other rail traffic.
A single yellow background speed sign applies to all rail traffic. Turnout speed signs have black text on a yellow background with a letter X before the numbers and identify the maximum speed for the turnout.
115 100 X15 C17-1.2
Advisory speed signs Advisory speed signs are provided where there is not enough signal sighting distance, to allow trains to stop if required at the second signal ahead and have red text on silver background, red on yellow, or yellow on blue, depending on the type of train.
110 80 40 © Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 181 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
C17-1.3
TMC 202
Freight train speed signs Freight train speed signs indicate a maximum speed for all freight trains travelling inside the area bounded by Ourimbah, Westmead, Casula and Unanderra and have yellow text on a blue background.
C17-1.4
Other signs Rolling stock prohibition signs indicate the point that medium or wide gauge rolling stock must not pass and have white text on red background. Electric train stop signs indicate the point that electric trains must not pass unless authorised to travel with pantographs lowered and have a black symbol on a yellow background or white text on a red background.
ELECTRIC TRAIN STOP Points clearance signs are provided at some locations to tell drivers that the train is clear of the relevant points and have white text on black background. Whistle signs are provided where drivers must sound the whistle before the front of the train passes the whistle sign and have black text on white background. WOLO signs indicate to a driver that a special speed restriction is in place due to hot weather. They have black letters on a yellow background and are placed at the beginning of the restricted zone within the metropolitan area.
C17-2
Temporary speed restrictions
C17-2.1
Applying temporary speeds When the condition of the track or structure is considered to be not suitable for normal speeds and repair work is required, a temporary speed restriction can be imposed until repair work is completed. The speed can be “wired on” and temporary Warning, Caution and Clearance boards are erected. If the speed restriction can be advertised in RIC Speed one week in advance, the use of telegrams to wire on the speed is not necessary. In an emergency situation (broken rail, misalignment, track geometry defect etc), you may need to apply a speed restriction at once. This speed restriction is “wired on” and the Network Control Officers must advise the trains of the reduced speed before entering the section.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 182 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
If you consider the line is unsafe for trains, emergency protection using the appropriate Network Rules should be implemented or protect the site with handsignallers until Warning, Caution and Clearance boards can be erected.
C17-2.2
Location of boards Train drivers MUST be able to see Warning, Caution and Clearance signs. They will take action based on the location of the signs. Therefore signs MUST be put: • On the LEFT hand side of the track. Single line and BiDirectional areas MUST be protected in both directions.
Overhead Wiring Structure Max. 3000
In Bi-Directional areas, the signs are placed on the right hand side for trains travelling in the wrong running direction.
C17-2.3
Min. 1800
Max. 2800
• Between 1800mm and 3000mm from the nearest running rail. • The bottom of the signs MUST be between rail level and 500mm above rail level. • Warning signs MUST be erected not less than 2500m from the affected area, Caution signs 50m before the affected area, and Clearance signs to be erected 50m beyond the affected area.
Rail Level
Speed plates Speed plates are fitted to the bottom of the Warning sign and the top of the Caution sign to indicate to train drivers what speed restriction applies. In some locations multiple speed restrictions will apply progressively in a track section and additional speed plates are added to the bottom of Caution signs to advise drivers of the speed applying to the next section.
C17-2.4
Intermediate warning signs (distance to caution) Where there is not enough track length to give 2500m warning distance, Intermediate Warning signs are used. The signs are standard warning signs with a ‘Distance to Caution sign attached at the bottom, and are placed on the secondary track before it enters the main line on which the speed applies. They
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 183 of 184 Version 2.3
RailCorp Engineering Manual — Track Track Fundamentals
TMC 202
can only be used where trains cannot exceed 40kph approaching the sign.
C17-2.5
Warning lights Warning lights MUST be fixed to the top of temporary speed signs in the area bounded by: • Helensburgh, Macarthur, Emu Plains and Cowan. • Newcastle, Fassifern and Telarah. • Thirroul and Unanderra. A Blue flashing light is attached to the Warning sign, an amber flashing light is attached to the Caution sign and a white flashing light is fixed to the Clearance sign.
© Rail Corporation Issued June 2012
UNCONTROLLED WHEN PRINTED
Page 184 of 184 Version 2.3
View more...
Comments
