Switches and Crossings

Transcription

1 Switches and Crossings Synopsis This document sets out general requirements for the design, inspection and maintenance of switches and crossings (S&C). It also defines particular requirements for fixed crossings. Signatures removed from electronic version Submitted by Steven Hayter Standards Project Manager Authorised by Brian Alston Controller, s This document is the property of Railtrack PLC. It shall not be reproduced in whole or in part without the written permission of the Controller, s, Railtrack PLC. Published by: Safety & Standards Directorate Railtrack PLC Evergreen House 160 Euston Road London NW1 2DX Copyright 2000 Railtrack PLC

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3 Page 1 of 11 Contents Section Description Page Part A Issue Record 2 Technical Content 2 Responsibilities 2 Compliance 2 Health and Safety Responsibilities 2 Supply 2 Part B 1 Purpose 3 2 Scope 3 3 Definitions 3 4 Principles 4 5 Requirements for Track Geometry Design 4 6 Requirements for Track System and Components 5 7 Requirements for Track Inspection, Testing and Track Recording 9 8 Requirements for Track Maintenance and Corrective Action 10 References 11 RAILTRACK 1

4 Page 2 of 11 Withdrawn Document Issue Record Part A This document will be updated when necessary by distribution of a complete replacement. Revisions have not been marked by a vertical black line in this issue, as the document has been revised throughout. Issue Date Comments One December 1995 Original Document Two December 2000 Revised document. Requirements for switches, switch diamonds and swing nose crossings transferred to GI/RT7004. Requirements for cast crossing inspections transferred to GC/RT5022. Technical Content Approved by: Derek Wolfendale, Principal Track and Structures Engineer, Railtrack S&SD. Enquiries to be directed to the Industry Safety Liaison Dept - Tel: Responsibilities s are mandatory on all members of the Railway Group * and apply to all relevant activities that fall into the scope of each individual s 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 Railtrack and the duty holders of the Railway Safety Cases accepted by Railtrack. Compliance The provisions in this document are to be complied with from 03 February 2001 except as specified below. Section 6.14 (Requirement for standard drawings) is to be complied with from 01 February Health and Safety Responsibilities Supply In issuing this document, Railtrack PLC makes no warranties, express or implied, that compliance with all or any documents published by the Safety & Standards Directorate 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. Controlled and uncontrolled copies of this document may be obtained from the Industry Safety Liaison Dept, Safety and Standards Directorate, Railtrack PLC, Evergreen House, 160 Euston Road, London, NW1 2DX. 2 RAILTRACK

5 Page 3 of 11 1 Purpose 2 Scope Part B The purpose of this document is to set out general requirements for the design, inspection and maintenance of switches and crossings (S&C). It also defines particular requirements for fixed crossings. The overall scope of s is set out in Appendix A of GA/RT6001. This document contains requirements that are applicable to the duty holders of the following category of Railway Safety Case: Infrastructure Controller. The requirements of this document apply to all S&C in running lines and sidings on Railtrack Controlled Infrastructure. Its validity is limited to: track with permissible or enhanced permissible speeds up to and including 140mph track which carries vehicles with axle loads no greater than 25.5 tonnes. Specific requirements for switches, switch diamonds and swing nose crossings are set out in GI/RT Definitions All technical terms used in this document, other than those given below, have the meanings defined in GC/RT5603. 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. Cast crossing Cast crossings are manufactured from cast steel either as a complete unit or as a cast centre block with welded on legs. 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. CWR Abbreviation for continuous welded rail. Rails installed in the track that have been welded together to form a single rail greater than a nominal 55m in length. Track constructed with continuous welded rail. 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. 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. RAILTRACK 3

6 Page 4 of 11 Withdrawn Document 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. 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. Reference specification A specification describing the minimum performance characteristics required from the track system. The performance characteristics may be achieved by using components other than those detailed within the specification. S&C Abbreviation for switches and crossings. Standard drawing A drawing showing critical dimensions with construction and maintenance tolerances for a generic type of S&C unit or component. Strengthened switch Switches designed for use in CWR without the need for adjustment switches to protect them from thermal forces. 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 given in GC/RT5023. Track gauge The distance between the running edges of the running rails in a track, measured at right angles to the rails in a plane 14mm below their top surface. Turnout route and through route in S&C A turnout route in S&C is one having a set in the stock rail at the switch toes. A through route has no set in the stock rail at the switch toes. Note that an equal split turnout has a set in both stock rails and that therefore both routes are turnout routes. 4 Principles This document supports HMRI Safety Principle 5: The track should provide for the safe guidance and support of trains. 5 Requirements for Track Geometry Design 5.1 Location of S&C in relation to track geometry Where practicable, S&C shall not be sited on: sharp horizontal circular curves; horizontal transition curves; highly canted curves; curves requiring negative cant on the turnout route through S&C; vertical curves. 4 RAILTRACK

7 Page 5 of 11 Requirements for track geometry design, including the requirements when it is necessary to locate S&C on a curved through route, are set out in GC/RT Location of crossings in relation to cant gradients Crossings shall not be located on a cant gradient (that is, the bearers shall not change rake through the crossing length). For the purpose of this requirement, a crossing shall be considered to extend to the 1m opening point between the running edges of the through route and turnout route. 6 Requirements for Track System and Components 6.1 Location of S&C Where practicable S&C shall not be sited in the following locations: within tunnels; on bridges, especially of the longitudinal-timbered type; in proximity to an overbridge with piers or abutments close to the track. Requirements for the assessment of track layouts for risks associated with train overruns are set out in GI/RT7006. Requirements for the location of trap points are set out in GK/RT General design requirements S&C shall be designed to suit the equivalent tonnage likely to use it and shall take into account track geometry, speed, direction of traffic, temperature variations and other relevant site conditions. 6.3 Reference specification for new construction: S&C for use in CWR S&C for use in CWR for new construction shall have performance characteristics comparable to or better than the reference specifications below. The reference specification for track category 1A shall be: 60 E 1 rail (formerly known as UIC 60 rail); cast centre block or cast monobloc crossings with weldable legs; strengthened switches; concrete bearers. The reference specification for track categories 1 and 2 shall be: 113A flat bottom rail; cast centre block or cast monobloc crossings; strengthened switches; concrete bearers. The reference specification for track category 3 and below shall be: 109lb flat bottom rail; part fabricated crossings; strengthened switches; hardwood bearers. The requirements for ballast and ballast profiles are set out in GC/RT5014. RAILTRACK 5

8 Page 6 of 11 Withdrawn Document 6.4 Reference specification for new construction: S&C for use in jointed track S&C for use in jointed track for new construction shall have performance characteristics comparable to or better than the reference specification below. 95lb RBS Bull Head rail or 109lb flat bottom rail; part fabricated crossings (track categories 3 and 4) or fully fabricated crossings (track categories 5 and 6); softwood bearers. The requirements for ballast and ballast profiles are set out in GC/RT Design of switches, switch diamonds and swing nose crossings Requirements for the design of switches, switch diamonds and swing nose crossings are set out in GI/RT Design of crossings The selection of crossings shall take into account the speed of traffic and equivalent tonnage using the line. Fixed acute (common) crossings shall not be used where the angle of the crossing is flatter than 1 in 35. Swing nose crossings shall be used where an acute crossing angle flatter than 1 in 35 is required. Fixed obtuse crossings shall not be used where: the angle of the crossing is flatter than 1 in 8; the permissible or enhanced permissible speed exceeds 105mph; the cant on either route through the crossing exceeds 100mm; negative cant occurs on either route through the crossing; the radius of either track is sufficiently small to give rise to an appreciable risk that a wheel flange may pass on the wrong side of a point rail nose. Switch diamonds shall be used where fixed obtuse crossings are not permitted for any of the reasons listed above. Fully fabricated crossings shall not be used where the permissible or enhanced permissible speed exceeds 75mph. The wheel transfer area between crossing nose and wing rail of fixed crossings shall be protected on the opposite running rail by a check rail on each route. Raised check rails shall only be used in S&C in third or fourth rail electrified areas where the raised check rail presents no possible conflict with the collector shoe. Requirements for cant deficiency limits at crossings are set out in GC/RT Specification of cast crossings The specification for cast crossings shall include requirements for: material quality and heat treatment; locations provided for bond attachments; any integral welds; manufacturing tolerances; repair classification and permissible repair areas. 6 RAILTRACK

9 Page 7 of Configuration, dimensions and spacing of bearers The configuration, dimensions and spacing of bearers in S&C shall be sufficient to: maintain track stability; maintain designed alignment geometry; provide uniform support to the S&C. The nominal spacing between bearers shall not be greater than 710mm centres. The spacing between individual bearers shall not be greater than 800mm centres. Where practicable, bearers of different materials (for example, softwood and hardwood; hardwood and concrete or concrete and steel) or bearers having differing soffit depths shall not be mixed in the same unit of S&C. Where a hollow bearer containing a point operating mechanism or other equipment is used, the depth of the bearer s soffit shall be approximately the same as those of the adjacent bearers. 6.9 Particular requirements for the configuration of bearers Where practicable, bearers shall be at right angles to the through route of S&C. Bearers under obtuse crossings shall be positioned at right angles to the centre line of the diamond. Bearers supporting crossing noses shall not be gapped in the adjacent four-foot. Elsewhere, to minimise the need for very long bearers, it is permissible to gap a bearer in the four-foot provided both adjacent bearers are continuous across the four foot and provide an effective gauge tie. Where practicable, long bearers supporting both through routes of a crossover shall be provided at and between the two crossings. For the purpose of this requirement, a crossing shall be considered to extend to the 1m opening point between the running edges of the through route and turnout route. Interlacing of bearers shall not be permitted in new designs of S&C. The longitudinal jointing (splicing) of bearers is only permissible where it cannot be avoided because of practical limitations on the size and weight of bearers. The Infrastructure controller shall have a specification for the longitudinal jointing of bearers, which shall ensure that the integrity of the S&C is not compromised, taking into account: the need to retain gauge and designed track intervals; the need to control cross levels to retain designed cant and to prevent twist faults. All longitudinal jointing (splicing) of bearers shall conform to the specification Position of chairs and baseplates on bearers Chairs and baseplates shall be positioned on bearers to provide sufficient distance between holding down screws or bolts and the edge of the bearer to ensure that: the chair or baseplate can be securely fixed to the bearer; the bearer will not be liable to splitting. The edge of chairs and baseplates (or conductor rail support on DC electrified lines) shall be nowhere less than 50mm from the ends of bearers. So far as is practicable, chairs or baseplates shall be positioned centrally (transversely) on the bearer. RAILTRACK 7

10 Page 8 of 11 Withdrawn Document 6.11 Drilling of concrete bearers The Infrastructure controller shall specify the position, method of drilling holes and types of inserts that may be used in concrete bearers to accept fastenings for rails, signalling equipment or other attachments. The specification shall ensure that the integrity of the bearers is not compromised (for example by cutting reinforcement or longitudinal splitting) in a way that could lead to their failure in service. Concrete bearers shall not be drilled other than in accordance with the specification Design and specification of other S&C components Requirements for rail support systems, including chairs, baseplates and bearers for S&C, are set out in GC/RT5015. Requirements for rail fastening systems, including clips, pads and insulators, are set out in GC/RT5013. Requirements for minimum rail lengths and location of rail joints are set out in GC/RT Flangeway gaps and check gauges GM/TT0089 sets out dimensional limits for wheels and wheel sets, including the distance between wheel flange backs. Flangeway gaps and check gauges shall be compatible with the dimensions set out in GM/TT0089. GM/TT0089 assumes a nominal check gauge of 1391mm Requirement for standard drawings Standard drawings shall be prepared for all generic types of S&C unit (for example, a CV9¼ turnout) showing critical dimensions with construction and maintenance tolerances. The dimensions shown on the standard drawings shall include dimensions defining: the flangeway gaps, check gauge and track gauge at crossings (see section 8.2); the position of check rails in relation to crossing noses; the geometry of check rail flares; the relationship (or stagger) of the two obtuse angled crossings of a diamond (see section 8.2); the acceptable positions for fishplated joints, including insulated joints. Standard drawings shall be prepared for all generic types of fixed crossings showing critical dimensions. The dimensions shown shall include dimensions defining the alignment and position of crossing noses in relation to running edges. Specific requirements for standard drawings for switches, switch diamonds and swing nose crossings are set out in GI/RT7004. The standard drawings required by this document shall be linked to those required by GI/RT7004 to give a comprehensive suite of standard drawings for S&C Acceptance of equipment and materials for use in Railtrack Controlled Infrastructure Requirements for the acceptance of systems, equipment and materials for use in Railtrack Controlled Infrastructure are set out in GI/RT RAILTRACK

11 Page 9 of 11 7 Requirements for Track Inspection, Testing and Track Recording 7.1 General inspection requirements General requirements for track inspection and maintenance are set out in GC/RT Inspection of rails, rail joints and cast crossings Requirements for the inspection of rails and rail joints, including particular requirements for the inspection of cast crossings, are set out in GC/RT Procedures for additional inspections The infrastructure controller shall have procedures for undertaking inspections of S&C in addition to those identified in sections 7.1 and 7.2. The procedures shall include: a) Inspections to check for correctness of check and wing rail flangeways; track and check rail gauge; and the relationship (or stagger) of the two obtuse angled crossings of a diamond (see section 8.2). b) Inspections to check that all bolts, screws and fastenings are fitted and correctly tightened. Where practicable, these inspections shall include observation of the passage of trains to assess the performance and behaviour of the S&C under traffic and to assess voiding below bearers. c) Inspections to determine the need for maintenance welding of crossings. Requirements for procedures for the inspection of switches, switch diamonds and swing nose crossings are set out in GI/RT7004. Procedures for the additional inspection of S&C required by this document shall be linked to those required by GI/RT7004 to give a comprehensive suite of procedures for S&C inspection. 7.4 Determination of intervals between additional inspections The infrastructure controller shall determine and document the required intervals between the additional S&C inspections set out in section 7.3, taking the following factors into account: Generic factors - track category; - types and configuration of S&C components. Local factors - predicted wear and damage from the usual traffic flow; - condition of components. Frequencies of inspection shall be reviewed when any of these factors change. 7.5 Follow up to additional inspections Reports of additional S&C inspections shall be reviewed to determine necessary actions. Arrangements shall be made to undertake any necessary actions within a timescale commensurate with expected deterioration of the conditions found and the likelihood and consequences of derailment. RAILTRACK 9

12 Page 10 of 11 Withdrawn Document 7.6 Records of additional inspections Records of all additional S&C inspections shall be kept for a minimum of 2 years. The records shall include: the identity and location of the S&C inspected; the date and method of inspection; the person undertaking the inspection; the faults and defects found; any subsequent actions taken; any decisions to take no action about reported faults or defects, together with the reasons for the decisions. 8 Requirements for Track Maintenance and Corrective Action 8.1 Maintenance of switches, switch diamonds and swing nose crossings Requirements for the maintenance of switches, switch diamonds and swing nose crossings are set out in GI/RT Flangeway gaps, check gauge and track gauge at crossings Flangeway gaps and check gauge shall be maintained to the dimensions and tolerances shown on the appropriate standard drawing (see section 6.14). The relationship (or stagger) of the two obtuse angled crossings of a diamond shall be maintained to the dimensions and tolerances shown on the appropriate standard drawing (see section 6.14) so that the gauge on the two routes is kept within correct limits. Requirements for track gauge are set out in GC/RT Temporary plain lining of obtuse angled crossings Where it is necessary to temporarily plain line an obtuse crossing by removal of a half set of the crossing, arrangements shall be made to provide a check rail to cover the remaining half set. 8.4 Actions to be taken on finding a broken, cracked or defective rail The actions to be taken on finding a broken, cracked or defective rail are set out in GC/RT RAILTRACK

13 Page 11 of 11 References GA/RT6001 GC/RC5603 GC/RT5013 GC/RT5014 GC/RT5015 GC/RT5021 GC/RT5022 GC/RT5023 GI/RT7002 GI/RT7006 GI/RT7004 GK/RT0064 GM/TT0089 s Change Procedures Standard Definitions of Civil Engineering Terms Track Standards Manual: Section 4 - Rail Fastening Systems Track standards Manual: Section 6 - Ballast and Formation Track Standards Manual: Section 5 - Rail Support Systems Track System Requirements Rails and Rail Joints Categorisation of Track Acceptance of Systems, Equipment and Materials for Use on Railtrack controlled infrastructure Prevention and Mitigatation of overruns - Risk Assessment Requirements for the Design, Operation and Maintenance of Points Provision of Overlaps, Flank Protection and Trapping Geometric Interfaces Between Railway Wheelsets and Track The Catalogue of s and the s CD-ROM give the current issue number and status of documents published by the Safety & Standards Directorate. HS(G)153/1 HMRI Railway Safety Principles and Guidance RAILTRACK 11