Track System Requirements Synopsis This document mandates requirements for the safe performance of the track system by specifying minimum requirements for the design, construction, inspection and maintenance of the track system and by specifying minimum actions to restore safety in the event of a system failure. Signatures removed from electronic version Submitted by Laura Beales Standards Project Manager Authorised by Anne E Blakeney Acting Controller, s This document is the property of the Rail Safety and Standards Board Limited. It shall not be reproduced in whole or in part without the written permission of the Controller, Railway Group Standards, Rail Safety and Standards Board. Published by: Rail Safety and Standards Board Evergreen House 160 Euston Road London NW1 2DX Copyright 2003 Rail Safety and Standards Board Limited.
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Page 1 of 76 Contents Section Description Page Part A General Information A1 Issue record 3 A2 Implementation of this document 3 A3 Scope of s 4 A4 Responsibilities 4 A5 Health and safety responsibilities 5 A6 Technical content 5 A7 Supply 5 Part B Introduction B1 Purpose 7 B2 Application of this document 7 B3 Definitions 10 B4 Principles 16 Part C Requirements for track geometry design C1 Normal limiting design values and exceptional limiting design values 17 C2 General horizontal alignment requirements 17 C3 Permissible speed 17 C4 Enhanced permissible speed 18 C5 Circular curves 19 C6 Transition curves 23 C7 Vertical alignment 24 C8 Requirements for location of S&C 25 C9 Records of track geometry 26 C10 Track geometry requirements for sidings 27 C11 Track gauge 28 C12 Rail inclination 28 Part D Requirements for the track system and components D1 General requirements for all track 29 D2 Ballast 29 D3 Rail supports 30 D4 Rail fastenings 33 D5 Other requirements for components 33 D6 Particular requirements for CWR 34 D7 Particular requirements for jointed track 36 D8 Conversion of jointed track to CWR 36 D9 Particular requirements for non-ballasted track 37 D10 Particular requirements for switches and crossings 38 D11 Particular requirements for special track features 39 Part E Requirements for track engineering work E1 Track undergoing renewal or remodelling 41 E2 Raising or removing speed restrictions 41 E3 Reopening of a line after engineering work 41 E4 Requirements for inspection and records in support of sections E2 and E3 42 RAIL SAFETY AND STANDARDS BOARD 1
Page 2 of 76 Part F Requirements for track inspection and recording F1 Introduction 44 F2 Competence requirements for track inspections 45 F3 Requirement to carry out track inspections 46 F4 Content of track inspections 46 F5 Requirements for basic track inspections 47 F6 Reduction of basic track inspection frequencies 49 F7 Requirements for supervisor s track inspections 50 F8 Requirements for track engineer s track inspections 50 F9 Track inspection frequencies at locations with particular risks 51 F10 Follow-up to track inspections 51 F11 Records of track inspections 51 F12 Requirements for track inspections in special circumstances 52 F13 Additionsl track inspections of S&C 53 F14 Additional track inspections of longitudinal timbers 54 F15 Track inspections in sidings 55 F16 Track geometry recording 55 Part G Requirements for track maintenance and corrective action G1 Track maintenance 57 G2 Track faults 57 G3 Track quality 59 G4 Maintenance of track stability 61 G5 Relationship between track and electrification equipment 63 G6 Special requirements for tunnels 64 G7 Special requirements for longitudinal timbers 64 G8 Broken and defective components 65 G9 Weather precautions 66 G10 Traction sander application 66 Appendices 1 Basic track inspections 68 2 Risk assessment factors to support reduced track inspection frequencies 73 References 75 2 RAIL SAFETY AND STANDARDS BOARD
Page 3 of 76 A1 Issue record Part A Issue Date Comments One April 2000 New document. Superseded Railway Group Standards GC/RT5010 and GC/RT5017 with some further additions. Two October 2003 Replaces issue one. Incorporates changes advised in GC/GN5523 and requirements held in GC/RT5011 issue two (see section A2), GC/RT5014 issue one and GC/RT5024 issue one. This document has been revised throughout therefore changes have not been indicated with a black line. This document will be updated when necessary by distribution of a complete replacement. A2 Implementation of this document The publication date of this document is 04 October 2003. This document comes into force on 06 December 2003. The dates by which compliance with the requirements of this document is to be achieved are set out in Part B2. Where those dates are later than the date on which this document comes into force, this is to give Railway Group members additional time to plan and commence implementation so as to achieve full compliance by the dates set out in Part B2. This document supersedes the following s, either in whole or in part as indicated: Railway Group Standard Issue No. Title RGS sections superseded by this document Date(s) as of which sections are superseded GC/RT5011 2 Switches and Crossings GC/RT5024 1 Rail Fastenings and Supports GC/RT5014 1 Track Standards Manual Section 6: Ballast and Formation 1 Track System Requirements All All 7.7, 7.8, 7.9, 7.13 and 7.14 All sections except those listed below 06 December 2003 06 December 2003 06 December 2003 (All other sections superseded by GC/RT5014 issue two Trackbed and Track Drainage from 07 August 2003) 06 December 2003 RAIL SAFETY AND STANDARDS BOARD 3
Page 4 of 76 Railway Group Standard Issue No. Title 1 Track System Requirements 1 Track System Requirements 1 Track System Requirements 1 Track System Requirements RGS sections superseded by this document 5.8 (Records of track geometry design) 6.5.1 (check rails on curves) 8.1.3 (Methods of undertaking track inspections) 9.2.2 (Twist faults) Date(s) as of which sections are superseded 03 April 2004 (date carried forward from issue one) 03 December 2005 07 June 2004 03 April 2004 issue 1 ceases to be in force and is withdrawn from 03 December 2005. GC/RT5024 issue 1 ceases to be in force and is withdrawn from 06 December 2003. GC/RT5014 issue 1 ceases to be in force and is withdrawn from 06 December 2003. GC/RT5011 issue 2 ceases to be in force and is withdrawn from 06 December 2003. A3 Scope of Railway Group Standards A4 Responsibilities The overall scope of s is set out in Appendix A of GA/RT6001. The specific scope of this document is set out in Part B2. s are mandatory on all members of the Railway Group* and apply to all relevant activities that fall into the scope of each Railway Safety Case. If any of those activities are performed by a contractor, the contractor s obligation in respect of s is determined by the terms of the contract between the respective parties. Where a contractor is a duty holder of a Railway Safety Case then s apply directly to the activities described in the Safety Case. * The Railway Group comprises Network Rail Infrastructure Limited, Rail Safety and Standards Board Limited, and the train and station operators who hold railway safety cases for operation on or related to infrastructure controlled by Network Rail Infrastructure Limited. Network Rail Infrastructure Limited is known as Network Rail. Rail Safety and Standards Board Limited is known as RSSB. 4 RAIL SAFETY AND STANDARDS BOARD
Page 5 of 76 A5 Health and safety responsibilities A6 Technical content In issuing this document, RSSB makes no warranties, express or implied, that compliance with all or any documents published by RSSB is sufficient on its own to ensure safe systems of work or operation. Each user is reminded of its own responsibilities to ensure health and safety at work and its individual duties under health and safety legislation. The technical content of this document has been approved by: Jon Taylor, Principal Track and Structures Engineer, RSSB Haydn Peers, Principal Rolling Stock Engineer, Principal Plant Engineer, RSSB Enquiries should be directed to RSSB Tel: 020 7904 7518 A7 Supply Controlled and uncontrolled copies of this document may be obtained from the Industry Safety Liaison Dept, Rail Safety and Standards Board, Evergreen House, 160 Euston Road, London NW1 2DX. RAIL SAFETY AND STANDARDS BOARD 5
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Page 7 of 76 B1 Purpose B2 Application of this document Part B Introduction This document mandates requirements for the safe performance of the track system by specifying minimum requirements for the design, construction, inspection and maintenance of the track system and by specifying minimum actions to restore safety in the event of a system failure. B2.1 To whom the requirements apply This document applies to duty holders of the infrastructure controller category of Railway Safety Case. B2.2 Compliance requirements The requirements of this document apply to all track in running lines and sidings on Network Rail controlled infrastructure. Its validity is limited to: a) track with permissible or enhanced permissible speeds up to and including 140 mph b) track which carries vehicles with axle loads no greater than 25.5 tonnes. B2.2.1 Compliance with Part C of this document The requirements of Part C of this document (requirements for track geometry design) apply to the design of new and re-laid track, and to the design of track geometry alterations (other than minor maintenance re-alignments). Requirements relating to permissible speed (section C3), enhanced permissible speed (section C4), cant deficiency (sections C5.8, C5.9, C5.10 and C5.11), rate of change of cant (sections C6.5 and C6.6), rate of change of cant deficiency (sections C6.7 and C6.8) and maximum vertical acceleration (section C7.3, first paragraph) also apply when the speed of trains using existing tracks is increased. Section C5.5 (Cant on curves with radii less than 320 m) and section C9 (Records of track geometry) also apply to existing track. Existing track may have been designed and constructed to standards that differ from those specified in Part C. Where site constraints make it not reasonably practicable to comply with the requirements for minimum horizontal radii (set out in sections C5.1 and C10.1) and vertical curves (set out in sections C7.3 and C10.2), it is permissible to retain the existing horizontal radii and vertical curves. A record of the decision to retain the existing track geometry shall be retained with the records required by section C9. The requirements of Part C of this document shall be complied with no later than 06 December 2003, except as set out below. The requirement for records of track geometry set out in section C9 shall be complied with no later than 03 April 2004 (date carried forward from issue one). When Approval in Principle is given before 06 December 2003, but the infrastructure has not yet been brought into service, the design shall be reviewed and, where reasonably practicable, brought into line with the requirements of this document. Where it is not reasonably practicable to do so, the situation shall be regularised by means of a non-compliance or derogation (see section B2.2.6). RAIL SAFETY AND STANDARDS BOARD 7
Page 8 of 76 B2.2.2 Compliance with Part D of this document The requirements of Part D of this document (requirements for track geometry design) apply to the design and construction of new and re-laid track. The requirements set out in sections D1.2, D2.2, D3.3, D3.4, D3.7, D3.9, D4.1 (last paragraph), D5.4, D5.5, D5.6, D5.7, D6.4, D7, D8, D9.2 (last paragraph), D11.1 and D11.3 also apply to existing track. The requirements of Part D of this document (requirements for the track system and components) shall be complied with no later than 06 December 2003, except as set out below. The requirement for the performance specification for the track system for all new construction set out in section D1 shall be complied with no later than 03 December 2005. The requirement for maximum permissible or enhanced permissible speed for the installation or replacement of crossings requiring tight jointed fishplates set out in section D6.3 shall be complied with no later than 03 December 2005. The requirement for insulated joints in check rails when replacing check rails or installing new check rails, set out in section D11.1, shall be complied with no later than 03 December 2005. When Approval in Principle is given before 06 December 2003, but the infrastructure has not yet been brought into service, the design shall be reviewed and, where reasonably practicable, brought into line with the requirements of this document. Where it is not reasonably practicable to do so, the situation shall be regularised by means of a non-compliance or derogation (see section B2.2.6). B2.2.3 Compliance with Part E of this document The requirements of Part E of this document (Requirements for track engineering work) shall be complied with no later than 06 December 2003. B2.2.4 Compliance with Part F of this document The requirements of Part F of this document (Requirements for track inspection and recording) shall be complied with no later than 06 December 2003, except as set out below. The requirement to inspect each through track of S&C individually set out in section F5.4 shall be complied with no later than 07 June 2004. B2.2.5 Compliance with Part G of this document The requirements of Part G of this document (Requirements for track maintenance and corrective action) shall be complied with no later than 06 December 2003, except as set out below. The requirement for the correction of twist faults between 1 in 126 and 1 in 199 in curves with a radius less than 400m, set out in section G2.2, shall be complied with no later than 04 December 2004. The requirement for records of rail stress condition in CWR set out in section G4.2 shall be complied with no later than 05 June 2004. B2.2.6 General compliance requirements Until the compliance dates, or the date by which compliance is achieved (if earlier), the applicable requirements of the predecessor documents shall continue to be met (see Part A for details). After the compliance dates, or after the date by which compliance is achieved (if earlier), Railway Group members shall not deviate from the requirements set out in this document. 8 RAIL SAFETY AND STANDARDS BOARD
Page 9 of 76 Where it is considered not reasonably practicable, to comply with the requirements set out in this document, authorisation not to comply shall be sought in accordance with GA/RT6001, GA/RT6004 or GA/RT6006. B2.3 Exclusions from the application of this document The requirements in this document do not apply to fastenings and supports for conductor rails. B2.4 Related requirements in other documents GC/RT5014 Trackbed and Track Drainage sets out requirements for the design, inspection and maintenance of the trackbed (made up of ballast, blanket and subgrade) and track drainage. GC/RT5022 Rails and Rail Joints sets out requirements for rails and rail joints and for their inspection. It also lays down requirements for minimum actions to restore safety when broken, cracked or defective rails and joints are found. GC/RT5023 Categorisation of Track sets out the procedure for categorising track in running lines by usage and speed, so that requirements relating to design, maintenance, renewal and inspection of the track may be specified and applied. GC/RT5033 Terminal Tracks Managing the Risk sets out the arrangements to be provided on terminal tracks to arrest a train and protect people, stations and structures from the effects of an overrun. GC/RT5201 Lineside Security sets out the management requirements for the control of unauthorised access to Network Rail controlled infrastructure. GC/RT5202 Vegetation - Managing the Risks sets out the management requirements for the control of vegetation on Network Rail controlled infrastructure. GC/RT5212 Requirements for Defining and Maintaining Clearances sets out requirements for monitoring and maintaining the position of the track relative to adjacent structures and tracks, to ensure that rail vehicles do not approach infrastructure or other vehicles too closely. It also sets out requirements for new, altered and temporary infrastructure relating to clearances. GE/RT8012 Controlling the Speed of Tilting Trains Through Curves sets out the means by which tilting trains are permitted to operate at higher speeds than nontilting trains around curves. GE/RT8047 Reporting of Safety Related Information sets out requirements for the reporting of safety-related information. Types of safety-related incidents needing to be reported include: a) derailments b) track buckles c) broken rails d) train driver reports of poor ride quality. GE/RT8050 Process for Dealing with Issues Between s and Technical Specifications for Interoperability (TSI) for High-Speed Operation sets out the process for Railway Group members to follow when an issue is found between complying with the requirements mandated by the Technical Specifications for Interoperability on high speed lines and those mandated in s. GI/RT7001 Management of Safety Related Records of Elements of the Infrastructure sets out the requirements for the management of safety related records of infrastructure. RAIL SAFETY AND STANDARDS BOARD 9
Page 10 of 76 GI/RT7002 Acceptance of Systems, Equipment and Materials for Use on Network Rail controlled infrastructure sets out the requirements for the acceptance of systems, equipment and materials for use on Network Rail controlled infrastructure. GI/RT7003 Management of Construction Work in the Operational Railway Environment sets out requirements for the management of safety of construction work carried out on (or which could affect the safety of) areas of railway infrastructure to which s apply. GI/RT7004 Requirements for the Design Operation and Maintenance of Points sets out requirements for the design, provision, inspection and maintenance of all types of points, including unworked points, derailers and scotch blocks. It includes requirements for the control, locking and detection of points by the signalling system and requirements for points acting as part of the track system. It also includes requirements for points heating. GI/RT7006 Prevention and Mitigation of Overruns Risk Assessment sets out the requirements for risk assessment of the design and operational use of track and signalling, so as to control the risks associated with trains exceeding the end of their movement authority. GK/RT0064 Provision of Overlaps, Flank Protection and Trapping sets out a range of controls to be applied to mitigate the consequences of a train overrunning a signal at danger. It includes specific requirements for the location of trap points. GO/RT3260 Competence Management for Safety Critical Work sets out the application of the Railways (Safety Critical Work) Regulations to Network Rail controlled infrastructure and defines requirements for systems for managing the competence and fitness of persons required to undertake such work. B2.5 Supporting documents Section C4.1 of this document (Enhanced permissible speed) is supported by GC/RC5521 Calculation of Enhanced Permissible Speeds for Tilting Trains. B3 Definitions Adjustment switch A scarf joint installed at the junction of continuous welded rail and jointed track to accommodate expansion of the continuous welded rail track. Adjustment switches are also used to protect track features such as S&C not designed for use in CWR and at the ends of some types of bridges (see section D6.4). Bearer A transverse beam that provides vertical and lateral support to S&C, usually cut from hardwood or softwood or made of steel or pre-stressed concrete. Ballast shoulder Ballast at the ends of sleepers and bearers to provide lateral track stability. Basic track inspection A frequent, regular track inspection carried out visually, either on foot, from a vehicle travelling at less than 10 mph or by alternative means (for example purpose designed video camera systems mounted on rail vehicles). No measurements are required as part of this inspection. See also track inspection, supervisor s track inspection and track engineer s track inspection. Bi-directional line A line on which the signalling system allows for trains to run in either direction. Buckle A track misalignment, typically caused by a combination of thermally induced forces, rail creep or work that has disturbed the stability of the track. 10 RAIL SAFETY AND STANDARDS BOARD
Page 11 of 76 Buffer stop An assembly provided at the end of a terminal track to arrest an overrunning train, designed to take the impact of the train at buffer or coupling height. Cab riding Inspections usually carried out from the driving cab of a train in daylight, but which can also be carried out from the trailing cab or the trailing coach of a train if equivalent visibility is available. Cant For the purposes of this document, cant is expressed as the design difference in level, measured in millimetres, between rail head centres (generally taken to be 1500 mm) of a curved track (compare with cross level ). Cant deficiency The difference between actual cant and the theoretical cant that would have to be applied to maintain the resultant of the weight of the vehicle and the effect of centrifugal force, at a nominated speed, such that it is perpendicular to the plane of the rails. For the purposes of this document, cant deficiency is always the cant deficiency at the rail head, not that experienced within the body of a vehicle. Cant gradient The rate at which cant changes in a specific length. Cast crossing Crossings manufactured from cast steel either as a complete unit or as a casting with welded on legs. Catch point Points provided for derailing a vehicle running back on a gradient in the wrong direction. Check gauge The distance between the running edge of a running rail and the bearing face of the opposite check rail, measured at right angles to the rails in a plane 14mm below their top surface. Check rail A rail or special section provided alongside a running rail at a specified dimension inside gauge to provide a flangeway, to give guidance to wheelsets by restricting lateral movement of the wheels. Clothoid spiral [transition curve] A transition curve between a straight and a curve where the curvature (the reciprocal of the radius) is proportional to the distance along the curve from its tangent point with the straight. Critical rail temperature The rail temperature to which continuous welded rail is permitted to rise before measures to protect traffic are taken. Crossing A cast or fabricated portion of the track layout which enables the rails of the two tracks to cross each other, while still providing support and guidance for smooth passage of the vehicle s wheels. Cross level The difference in level between the two running rails of a track. In this document cross level relates to measurements, taken on curved or straight track with or without cant applied, that are used to identify track geometry faults including twist faults, cyclic top faults and faults in applied cant (compare with cant ). RAIL SAFETY AND STANDARDS BOARD 11
Page 12 of 76 Curvature The reciprocal of the radius of a curve. Cyclic top Cyclic top is the term used to describe a series of regular dips in the vertical alignment of one or both rails. They may not always be apparent visually because other top irregularities may obscure the cyclic pattern. Cyclic irregularities in track geometry have the potential, when combined with a vehicle s natural vertical response for a given speed and load, to cause a derailment. CWR Abbreviation for continuous welded rail. 1) Rails installed in the track that have been welded together to form a single rail greater than a nominal 55 m in length. 2) Track constructed with continuous welded rail. Dangerous goods For the purpose of this standard only, dangerous goods are those in class 1, 2.1, 2.3, 3 Group A and 7 as set out in GO/RT3053/A. Daylight Natural light between the hours of sunrise and sunset. Enhanced permissible speed The permitted speed (higher than the permissible speed) over a section of line which applies to a specific type of train operating at cant deficiencies in excess of those permitted at the permissible speed. Enhanced permissible speeds are detailed in the Sectional Appendix. There may be more than one enhanced permissible speed applicable to a given section of line. Flange The projecting rim of a rail vehicle wheel. Flangeway gap The gap provided to permit the passage of the wheel flanges of rail vehicles, for example between a check rail and a running rail. Fully fabricated crossing Fully fabricated crossings are made by machining rolled rails to produce a point rail and a splice rail fastened together with bolts or multi-groove locking pins. The wing rails are produced from rolled rail and are fastened to the vee by bolts or multi groove locking pins. Insulated rail joint A rail joint in which one rail is electrically insulated from an abutting rail. Jointed track A method of track construction where rails are joined together by fishplates, with an expansion gap between rail ends. Level crossing An intersection at the same level of a road, footpath or bridleway and one or more railway tracks. Lightweight sleepers Sleepers installed in CWR or jointed track that have reduced resistance to lateral forces when compared with concrete sleepers, for example softwood sleepers and non-spade ended steel sleepers. 12 RAIL SAFETY AND STANDARDS BOARD
Page 13 of 76 Loaded track gauge The track gauge measured in a loaded condition, representing the track gauge under the passage of trains. See also track gauge. Longitudinal timber A timber parallel to and supporting a running rail. Misalignment Deformation or displacement of a rail or track from its designed alignment. Negative cant Cant is negative when the inner rail of a curve track is raised above the level of the outer rail. Also known as adverse cant. Non-ballasted track Track that is not supported on ballast, including concrete slab track, track supported on longitudinal timbers and directly fastened track on bridges. Obtuse crossing An assembly to permit the passage of wheel flanges where two rails intersect at an obtuse angle. Off-track items [to be inspected] Items in the general railway environment visible from the track. Typically off-track items are located in the area between boundary fences and the ballast shoulders of a track, but include structures spanning tracks. On-track items [to be inspected] Items forming the track structure, including rails, fastenings, sleepers and ballast. Typically on-track items are located in the area between the outer edges of the ballast shoulders of a track or number of tracks. Overspeed The amount by which the actual speed of a train could exceed the enhanced permissible speed for any reason. Part fabricated crossing Part fabricated crossings have either welded vees, cast vees or forged noses. The wing rails are produced from rolled rail and are fastened to the vee by bolts or multi-groove locking pins. Also known as semi-welded crossings. Permissible speed The maximum permitted speed over a section of line that applies to trains when not operating at an enhanced permissible speed. Permissible speeds are detailed in the Sectional Appendix. Plain line Track not incorporating switches and crossings. The term plain line therefore excludes the through route of S&C. Rail fastenings Any device used to secure running rails into chairs or baseplates or directly to sleepers, bearers or other rail supports. Rail pad A resilient layer fitted between a rail and the supporting sleeper or baseplate. Rail rotation The action of the rail turning about its longitudinal axis. If the rails rotate outwards the wheelsets may derail into the four foot. RAIL SAFETY AND STANDARDS BOARD 13
Page 14 of 76 Rail supports The means by which running rails are supported and the loads imposed on the rails by the vehicles being carried are transmitted to the ballast or other supporting structures. Rail supports usually take the form of sleepers or bearers, which may or may not be fitted with chairs or baseplates. Chairs and baseplates, together with the fastenings connecting them to sleepers, bearers or other support structures, form an integral part of the rail support. Rate of change of cant The rate at which a vehicle experiences the change in design cant measured in millimetres per second. Rate of change of cant deficiency The rate at which a vehicle experiences the change in design cant deficiency measured in millimetres per second. Reverse curve Two abutting curves of opposite flexure or hand. Running line A line as shown in Table A of the Sectional Appendix. Serviceable component A component that has been lifted from the site where it was originally installed as new and that has then been installed in the track at another site, usually in a lower category line. Slab track Non-ballasted track utilising a continuous concrete slab, including paved concrete track and monobloc or twin block sleepers embedded in concrete. Sleeper A transverse beam that provides vertical and lateral support to plain line running rails, rail fastenings and where appropriate check rails, guard rails, conductor rails and ancillary operating equipment. Standard deviation Standard deviation is a universally used scientific measure of the variation of a random process. Track profiles have been found to have sufficiently similar statistical properties to random processes to enable a measure of the magnitude of track irregularities to be obtained from the standard deviation (SD) of the vertical and horizontal profile data. This form of analysis provides track quality indices. Standard drawing A drawing showing typical critical dimensions with construction and maintenance tolerances for a generic type of S&C unit or component. Stress free temperature The rail temperature at which CWR is in neither compression nor tension. Supervisor The person who is responsible for the stewardship of the line in a given area and who determines the actions necessary to respond to reports of basic track inspections. A supervisor is able to demonstrate competence through knowledge and experience. People undertaking supervisor s duties are not necessarily designated supervisors. Supervisor s track inspection A regular track inspection carried out on foot by a supervisor that includes measurements of cross level and track gauge. See also track inspection, basic track inspection and track engineer s inspection. 14 RAIL SAFETY AND STANDARDS BOARD
Page 15 of 76 Switches A set of switches consists of two fixed stock rails with their two associated moveable rails. A set of switches counts as one point end. S&C Abbreviation for switch and crossing. A track layout incorporating switches and/or crossings that allows one track to cross another or diverge from or merge with another. Switch toe The end of the switch rail that is traversed first by a vehicle negotiating the switch in the facing direction. Technical specifications for interoperability Technical specifications for interoperability (TSIs) are the requirements for six of the eight sub-systems of a high speed-railway (as defined in the Directive 96/48/EC) by which the essential requirements for establishing compatibility between these sub-systems of the trans-european high-speed rail system (designated high-speed Trans European Network routes) are defined. Through route and turnout route in S&C In most S&C the through route is the one that carries the majority of traffic and is usually the route through which permissible speed remains unchanged. The turnout route is typically the one that carries less traffic and usually has a permissible speed substantially lower than that of the through route. Tight joint Non-insulated connection of two rails by means of specially drilled fishplates and rail fastening devices but without an expansion gap between the rail ends. Toe load The load exerted by a rail fastening on the foot of a flat bottom rail. Track bed A general term referring to the ballast, blanket and subgrade. Track category The classification of a section of track by usage and speed, so that requirements relating to design, maintenance, renewal and inspection of the track may be specified and applied. The procedure for categorising track is set out in GC/RT5023. Track engineer The engineer responsible for the maintenance of the track in a given area. A track engineer is able to demonstrate competence through knowledge and experience, usually being qualified in either a civil or mechanical engineering discipline. People undertaking track engineer s duties are not necessarily designated track engineers. Track engineer s track inspection A regular track inspection at extended intervals carried out on foot by a track engineer. See also track inspection, basic track inspection and supervisor s track inspection. Track fault A hazardous track geometry condition requiring remedial attention. In this document, the conditions covered by this term include twist (unintentional or non-compliant variation in cross level), track gauge, vertical profile (including cyclic top) and lateral alignment. RAIL SAFETY AND STANDARDS BOARD 15
Page 16 of 76 Track gauge The distance between the running edges of the rails in a track, measured without load at right angles to the running edges of the rails in a plane 14 mm below their top surface. See also Loaded track gauge. Track inspection An inspection carried out to identify faults and defects in the track system and its immediate environment that, if not addressed, could adversely affect the safety of the railway. See also basic track inspection, supervisor s track inspection and track engineer s track inspection. Track system The assemblage of rails, rail supports, rail fastenings, sleepers, timbers or bearers and ballast or other forms of support, acting together to provide guidance and support for rail vehicles. Transition curve A curve between a straight and a curve, or between curves of different radius, along which the radius changes in a regular (though not necessarily uniform) manner. Twist fault A difference in cross-levels over a short distance (usually measured over 3 m) that is greater than a predetermined amount. Twist rail A length of rail that changes in inclination from generally 1 in 20 to generally vertical. Vertical curve A curve joining two track gradients in their vertical alignment. B4 Principles This document supports HM Railway Inspectorate Safety Principle 5: The track is to provide for the safe guidance and support of vehicles. 16 RAIL SAFETY AND STANDARDS BOARD
Page 17 of 76 C1 Normal limiting design values and exceptional limiting design values Part C Requirements for track geometry design This section specifies normal limiting design values and exceptional limiting design values for track geometry parameters. When a design value is quoted without being described as either normal or exceptional, it is the only limiting value and no exceptional limiting value is permitted. Where design values exceeding the normal limiting design values are used, the increase in risk arising from their use shall be justified by a competent person and measures shall be put in place to manage the increased risk. Records of the justification made shall be kept with the design records required by section C9. Exceptional limiting design values shall not be exceeded. C2 General horizontal alignment requirements On running lines, horizontal alignments shall consist of circular curves and straight track connected where necessary by transition curves. The minimum length of each geometrical element shall be appropriate to the length and characteristics of vehicles likely to use the track. The design of horizontal alignments shall allow for the effective maintenance of track geometry, taking into account the proposed methods of maintenance (mechanical or manual). Restrictions on the location of station platforms in relation to the horizontal alignment of track are set out in GC/RT5161. The requirements for the alignment of track at buffer stops and arresting devices are set out in GC/RT5033. C3 Permissible speed The permissible speed on a curve shall be calculated taking account of the following factors: a) the radius of the curve b) the applied cant c) the permitted values of cant deficiency d) the permitted values of rates of change of cant and cant deficiency on the transition curves either side of the circular curve. There could be reasons other than track geometry design that restrict the permissible speed, for example the ability to maintain the track to sufficiently high track quality standards (see section G3), the nature of the signalling system, or the strength of structures. Section D6.3 limits the installation or replacement of crossings requiring tight joint fishplates to sites where the maximum permissible or enhanced permissible speed does not exceed 90 mph. This section also permits higher speeds in exceptional circumstances. Section D7.1 limits the maximum permissible or enhanced permissible speed on jointed track to 90 mph. RAIL SAFETY AND STANDARDS BOARD 17
Page 18 of 76 Section D9.2 requires that the permissible or enhanced permissible speed on track supported on longitudinal timbers shall not normally exceed 100 mph. This section also permits higher speeds in exceptional circumstances. Section D10.1 limits the maximum permissible or enhanced permissible speed for fully fabricated crossings to 75 mph. Section D11.3 limits the maximum permissible or enhanced permissible speed to 90mph on catch points. The requirements to be met before permissible speeds are altered are set out in GK/RT0007. C4 Enhanced permissible speed C4.1 Calculation of enhanced permissible speed The conditions under which trains are permitted to travel at an enhanced permissible speed are set out in GE/RT8012. The enhanced permissible speed shall be calculated for each type of train on each curve. The speed on each track of a double or multiple line shall be considered separately. On bi-directional tracks, the speed in each direction shall be considered separately. The infrastructure controller shall have a procedure for calculating enhanced permissible speeds meeting the requirements of this section. The procedure shall also set out the method of gaining technical approval for the calculated enhanced permissible speed. The calculation of enhanced permissible speed shall take account of the factors listed in section C3 together with the following additional factors: a) the maximum cant deficiency at which the train is designed to travel b) the dynamic roll-over resistance of the train (see GM/RT2141) c) the maintenance tolerances on cant (the amount by which, in practice, the applied cant could be less than its design value) d) the maintenance tolerances on curvature (the amount by which, in practice, the curve radius could be less than its design value) e) the expected local wind conditions f) the effect of wind on the train, taking into account the characteristics of the train (see GM/RT2142) g) the system adopted for controlling the speed of the train and the extent to which overspeed can occur (see GE/RT8012) h) a safety margin equivalent to no less than 50 mm of cant deficiency. The enhanced permissible speed shall ensure that the likelihood of overturning is within tolerable limits. The value of the factors used in the calculation of enhanced permissible speeds shall be reviewed at five yearly intervals to determine their continuing validity. 18 RAIL SAFETY AND STANDARDS BOARD
Page 19 of 76 C4.2 Maximum wind speeds It is permissible to choose a fixed maximum wind speed when calculating enhanced permissible speeds on a particular curve provided: a) effective controls are in place to ensure that the speed of trains is reduced to a value not greater than the permissible speed whenever the wind speed exceeds, or is predicted to exceed, the chosen maximum wind speed on the curve b) the procedures for implementing the controls to reduce the speed of trains are fully documented and made available to all those responsible for the safe operation of trains. It shall also be permissible to choose a fixed maximum wind speed when calculating enhanced permissible speeds on a particular curve provided wind barriers or fences are in place that are demonstrated to limit the wind speed on the curve to the chosen maximum wind speed. C4.3 Maximum values for loss of cant and reduction in curve radius It is permissible to choose fixed maximum values for loss of cant and reduction in curve radius when calculating enhanced permissible speeds provided: a) effective systems are in place for monitoring track geometry and maintaining it to a standard that ensures the chosen maximum values for loss of cant and reduction in curve radius are never exceeded b) the chosen maximum values for loss of cant and reduction in curve radius are fully documented and made available to those responsible for the maintenance of the track. C4.4 Records of the calculation of enhanced permissible speed Detailed records of the calculation of the enhanced permissible speeds shall be retained with the design records required by section C9. C4.5 Enhanced permissible speed for S&C Enhanced permissible speeds shall not be permitted on the turnout route of S&C. C5 Circular curves C5.1 Minimum radii Horizontal curve radii shall be selected to take account of the curving characteristics of vehicles likely to use the track. The normal minimum radius on passenger running lines shall be 200 m. The exceptional minimum radius on passenger running lines shall be 150 m. The normal minimum radius on non-passenger running lines shall be 150 m. The exceptional minimum radius on non-passenger running lines shall be 125 m. C5.2 Reverse curves The need for a length of straight track or transition between small radius reverse curves shall be considered, taking account of the following factors: a) the ability to traverse the curves of vehicles likely to use the line b) the likelihood of buffer locking c) vehicle coupling and interconnection designs. A length of straight track not less than 3m long shall be provided between the reverse curves if one of the curves has a radius of less than 160m. RAIL SAFETY AND STANDARDS BOARD 19
Page 20 of 76 C5.3 General requirements for cant The cant selected for a curve shall take into account: a) the proportions of the various types of traffic using the line, considering relative speeds and axle loads, and the resultant variation in lateral force and loading on both rails b) structure, passing and electrical clearances c) relative levels of adjacent tracks d) the permissible speed and any enhanced permissible speeds e) the permitted values of cant deficiency f) the permitted values of cant gradient and rates of change of cant and cant deficiency on the transitions either side of the circular curve g) the presence of S&C and the permitted value of negative cant. The cant on each track of a double or multiple line shall be considered separately. C5.4 Limiting design values for cant C5.4.1 Normal limiting design values The normal limiting design values for cant shall be: a) 110 mm adjacent to station platforms b) 110 mm on fixed obtuse crossings c) 150 mm elsewhere. C5.4.2 Exceptional limiting design values The exceptional limiting design values for cant shall be: a) 130 mm adjacent to station platforms b) 110 mm on fixed obtuse crossings (unchanged from normal limiting design value) c) 180 mm elsewhere. C5.5 Cant on curves with radii less than 320 m The cant on curves with radii less than 320 m shall not exceed C MAX, where C MAX is given by the lesser of: a) C MAX = (R - 50) / 1.5, where C MAX is in mm and R is the curve radius in metres. b) C MAX = the limiting value set out in section C5.4. Where existing small radius curves are discovered to have an installed cant exceeding the limits specified in this section, action shall be taken to reduce the cant. Where reasonably practicable, the cant shall be reduced within six months of discovery to a value not greater than specified in this section. C5.6 Negative cant Negative cant shall only be permitted on the turnout route through S&C and in the plain line immediately adjoining the S&C. On fixed obtuse crossings the normal limiting design value for negative cant shall be zero and the exceptional limiting design value shall be 65 mm. Elsewhere negative cant shall not exceed 80 mm. 20 RAIL SAFETY AND STANDARDS BOARD
Page 21 of 76 C5.7 Design cant excess On large radius curves where there is a significant difference between the normal speed of passenger trains and the normal speed of freight trains the cant is usually set by the maximum speed of the passenger trains. This will result in the freight trains operating on a cant significantly greater than their equilibrium cant and a consequent higher loading of the low rail. The infrastructure controller shall specify design limits on cant excess. C5.8 Cant deficiency at permissible speed C5.8.1 Normal limiting design values The normal limiting design value for cant deficiency shall be: a) 110 mm on plain line CWR b) 110 mm on the through route of S&C designed for use in CWR without adjustment switches c) 110 mm on the turnout route of S&C where designed to accommodate this value of cant deficiency d) 75 mm on fixed obtuse crossings e) 90 mm elsewhere. C5.8.2 Exceptional limiting design values An exceptional limiting design value for cant deficiency on plain line jointed track of 110 mm is permissible for diesel multiple units with axle weights less than 13 tonnes fully seated (all seats full) and fitted with bogies and air suspension, provided: a) the intrinsic track quality has been assessed and is considered suitable b) the condition of rail joints has been assessed and is considered suitable. An exceptional limiting design value for cant deficiency on plain line CWR of 150 mm is permissible for vehicles, other than freight vehicles, accepted for running at this cant deficiency, provided no features likely to contribute to lateral misalignment are situated on the transition or circular curve. Features considered likely to contribute to lateral misalignment shall include catch points, adjustment switches, level crossings, longitudinal timbers and directly fastened track on bridges. C5.9 Cant deficiency at switch toes It is permissible for the theoretical cant deficiency at switch toes to exceed the limiting values specified in section C5.8 but shall not exceed 125 mm. In order to assess the permissible speed it is necessary to calculate the radius at the switch toe. The radius shall be obtained by calculating the offset at the toe based on a 12.2 m chord centred about the switch toe. RAIL SAFETY AND STANDARDS BOARD 21
Page 22 of 76 C5.10 Cant deficiency on plain line at enhanced permissible speed C5.10.1 General requirements Cant deficiencies exceeding those set out in section C5.8 are permissible on CWR plain line, provided no features likely to contribute to lateral misalignment are situated on the transition or circular curve. Features considered likely to contribute to lateral misalignment shall include catch points, adjustment switches, level crossings, longitudinal timbers and directly fastened track on bridges. The limiting design values set out in sections C5.10.2 and C5.10.3 shall be reduced where necessary to meet the requirements of section C4. C5.10.2 Normal limiting design values The normal limiting design values for cant deficiency at enhanced permissible speed shall be: a) 110 mm for curves under 400 m radius b) 185 mm for curve radii less than 700 m but greater than or equal to 400 m c) 265 mm for curve radii greater than or equal to 700 m. C5.10.3 Exceptional limiting design values The exceptional limiting design values for cant deficiency at enhanced permissible speed shall be: a) 150 mm for curves under 400 m radius b) 225 mm for curve radii less than 700 m but greater than or equal to 400 m c) 300 mm for curve radii greater than or equal to 700 m. C5.11 Cant deficiency on the through route of S&C at enhanced permissible speed C5.11.1 Limiting design values The normal limiting design values for cant deficiency on the through route of S&C shall be the same as those at permissible speed set out in section C5.8.1. Exceptionally, a cant deficiency higher than the normal limiting value is permissible on S&C designed for use in CWR without adjustment switches, up to a limit of 200 mm, provided the radius is greater than or equal to 400 m. Where a cant deficiency higher than the normal limiting value is proposed, its value shall be assessed, taking into account the following factors: a) any special features incorporated into the S&C that increase the fixity of the track alignment and crosslevel and eliminate potential sources of misalignment b) the track geometry on the approach to the S&C, including the proximity of any designed change in cant deficiency c) the proposed maintenance regime for the section of track concerned d) any relevant local features or sources of risk to trains. Detailed records of the assessment shall be retained with the design records required by section C9. C5.11.2 Requirements for can deficiencies above 110 mm Where cant deficiencies above 110 mm are proposed, the use of S&C requiring adjustment switches is not permitted. The S&C shall be of a design with flat bottom rails, concrete bearers and high speed check rails with extended entry flares or other design with equivalent performance. In such layouts it is permissible to use hollow steel bearers for S&C drive and detection mechanisms. 22 RAIL SAFETY AND STANDARDS BOARD