Control Of Points. Withdrawn Document Uncontrolled When Printed. Railway Group Standard. Issue One Date July 1997

Transcription

1 Date July 1997 Signatures removed from electronic version Submitted by... Richard Genner Nominated Responsible Manager Approved by... Philip Wiltshire Chairman, Train Control & Communications Subject Committee Approved by... Michael Harwood Chairman, Operations Standards Subject Committee Authorised by Synopsis: This standard sets out the principles for the control of points by the signalling system. 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, Safety Standards, Railtrack PLC. Published by Safety & Standards Directorate Railtrack PLC Floor 2, Fitzroy House 355 Euston Road London NW1 3AG Copyright 1997 Railtrack PLC R Illingworth... for Dr M Walter Controller, Safety Standards

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3 Date July1997 Page 1 of 8 Contents Description Page Part A Part B Issue record 2 Responsibilities 2 Compliance 2 Health and Safety Responsibilities 2 Supply 2 1 Purpose 3 2 Scope 3 3 Definitions 3 4 General Requirements 4 5 Requirements for Manual Operation of Power Worked Points 6 6 Equipment Performance Requirements 6 7 New and Redundant Points 7 References 8 R A I L T R A C K 1

4 Date July 1997 Page 2 of 8 Part A Issue record Responsibilities This standard will be updated when necessary by distribution of a complete replacement. Amended or additional parts of revised pages will be marked by a vertical black line in the adjacent margin. Issue Date Comments One July 1997 This standard supersedes SSP26 paragraphs 1, 2 and 3; GS/ST0081 paragraph s are mandatory on all members of the Railway Group* and apply to all relevant activities which fall within 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 the contractor is himself a duty holder of a Railway Safety Case then s apply directly to the activities described in his Railway Safety Case. *The Railway Group comprises Railtrack and the duty holders of Railway Safety Cases accepted By Railtrack Compliance Health and Safety Responsibilities Supply The provisions of this are mandatory for design and implementation work undertaken on schemes for which the Signalling Scheme Plan is approved on or after 7th February Retrospective action is not required in respect of existing layouts and Signalling Scheme Plans approved prior to 7th February Railtrack shall consider the need to meet the provisions of this standard for alterations effected on or after 7th February 1998 to Signalling Scheme Plans approved prior to 7th February Section 5, paragraph 3 shall not prevent new installations of an existing type of electro-pneumatic point machine which may currently disconnect the detection by means of a key. In authorising this standard, Railtrack PLC makes no warranties, express or implied, that compliance with all or any of Railway Group Standards 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 standard must be obtained from the Catalogue Secretary, Railtrack Safety & Standards Directorate, Floor 2, Fitzroy House, 355 Euston Road, London NW1 3AG. Telephone: Facsimile: or (BT) or (BT) 2 R A I L T R A C K

5 Date July1997 Page 3 of 8 Part B 1 Purpose To define the requirements for the control of points by the signalling system to ensure the safe movement of trains. 2 Scope This standard applies to all point ends whose position is detected by the signalling system, whose movement is controlled or supervised by the signalling system, or whose operation is supervised by a signaller, including ground frames. Provision for manual operation of power worked points is also included. Train Operated Points are excluded from this standard and are the subject of, GK/RT0065. This standard relates to the control of points in the required position and detection and indication of the state of those points. The standard does not deal with the functionality of the mechanism to achieve this. Internal interlocking controls are specified in Railway Group Standard GK/RT0060. Although the safety of points depends also on the construction of the permanent way, this standard is confined to those factors which affect the signalling system. 3 Definitions Points: The items of permanent way which may be aligned to one of two positions, normal or reverse, according to the direction of train movement required. For the purpose of this standard the term points includes moveable items of permanent way such as separate switch rails, coupled switch rails, switch diamonds, swing nose crossings, derailers or scotch blocks, but excludes moveable items such as swing bridges. Point End: For the purpose of this standard the term includes a moveable item of permanent way such as a separate switch rail, a pair of coupled switch rails, one half of a switch diamond, a swing nose crossing, a derailer or a scotch block but excludes a moveable item such as a swing bridge. Normal and Reverse: The two defined states of a point end or associated controlling device. The determination of the normal (and hence reverse) position is arbitrary, usually defined by some convention at Signalling Scheme Plan development. Typical conventions define normal as being for the use or protection of the most used route or of the highest speed route. Correspondence: Correspondence occurs when the detected position of relevant point ends matches the normal or reverse position of the controlling device. Out of Correspondence: The term used to describe points which are not in correspondence. Detection: The proof of the position of the points, normal or reverse, to the interlocking equipment. R A I L T R A C K 3

6 Date July 1997 Page 4 of 8 Split Detection: The proof and indication to the interlocking of the position of multiple-ended sets of points, individually for each point end. External Command: An instruction sent to the point mechanism by the interlocking to send the point ends to the normal or reverse position. 4 General Requirements 4.1 Integrity Equipment integrity levels shall be appropriate to the risks associated with train movements, traversing or protected by the points. This specifically includes:- the movement of points the locking of points the detection of the switch rails relative to the stock rails the transmission of commands from the interlocking the transmission of detection information to the interlocking associated monitoring and diagnostic systems This integrity level of the point equipment (and its reliability) shall additionally apply to the equipment when not connected to the signalling system. 4.2 Operation All points, except hand points and spring points, shall be controlled to the normal or the reverse position. The point operating mechanism shall only move in response to an external command. The point operating mechanism shall move all moveable track components necessary for the safe passage of trains. The point operating mechanism shall maintain all moveable track components in the required position during the passage of a train. When the points are in either the normal or reverse position, the open switch rail shall provide adequate clearance for wheel flanges. The clearance for wheel flanges and the correct rail gauge shall be maintained throughout the length of the switch rail and, where necessary, a supplementary operating mechanism(s) shall be provided. 4.3 Facing Point Locking The point operating mechanism shall include a facing point lock, or other similar device, to physically lock the switch rails in position. Derailers, scotch blocks and hand points are excluded from this requirement. On other than running lines and for mechanical installations on running lines, where it can be demonstrated that the risk of derailment is negligible the facing point lock may be omitted. 4 R A I L T R A C K

7 Date July1997 Page 5 of 8 There shall be a means of securing the points to the position to which they are controlled and an indication to the signalman that the points are in the controlled position. 4.4 Detection Normal or reverse detection shall be mechanically proved or shall be electrically indicated to the signalling system when all components of the relative point ends are in the controlled position. Mechanical proving is only permitted where there is mechanical operation of the points and also mechanical operation of any facing direction signals, for further detail see the detection chart in section 5 of GK/RT0039. Normal or reverse detection shall only be proved or indicated when the open switch rail provides adequate clearance for wheel flanges. Where a facing point lock or similar device is provided, detection shall only be proved when the point lock is engaged (ie. points locked). Except for mechanical signalling (i.e. control by mechanical interlocking), the detection shall only be effective if it is in correspondence with the controlling devices. For mechanical signalling, correspondence requirements are specified in section 5 of GK/RT Unified Control All point ends shall be configured in such a way as to maximise reliability and safety under normal and degraded operation. The interlocking shall command the two point ends of a switch diamond to operate together and a swing nose crossing to operate with its associated switch rails unless the risks of not so doing are fully controlled. The signalman s control shall be from a single device. Other point ends may be operated together where there is an advantage in doing so (e.g. simplification of interlocking, economy of control equipment). In such cases, the signalman's control shall be from a single device and where an indication is necessary, a comprehensive indication (combined with additional point ends or as part of a split detection system) shall be provided. When it is intended to combine point ends, consideration shall be given to any secondary hazards arising from equipment failure. Point ends that are operated together can have a split detection system to facilitate train movements when there is a partial failure, but subject to the above restriction on switch diamonds and swing nose crossings. The detection system shall not be split into more than two parts. When there is a failure (total or part) of a split detection indication, train movements shall be restricted in accordance with the Rule Book requirements by the signalbox instructions. R A I L T R A C K 5

8 Date July 1997 Page 6 of Other Requirements Point operating mechanisms (all types) shall include a means of manually securing both open and closed switch rails on site, once operated, with a minimum amount of additional equipment. A padlocking facility shall also be available. Derailers and scotch blocks shall have equivalent facilities. It shall be possible to regain correspondence after such correspondence has been lost e.g. power worked points should continue to be operable after being manually worked. The list of references identifies s containing related or additional requirements. 5 Requirements for Manual Operation of Power Worked Points Facilities shall be provided to permit manual operation of point ends, independently of the power source and commands from the interlocking. Enabling of manual operation shall disconnect the point end(s) from the power source. Further power operations by the interlocking shall be prevented until the points operator has operated a reset or reconnection device. For electro-pneumatic points, it is additionally permitted to disconnect the interlocking commands and locally operate the point end(s) from the pressurised air supply. Selection of manual operation of points shall not disconnect the means of communication of detection to the interlocking. Control equipment for manual operation shall be secured such that access to control devices is available only to authorised persons. Control equipment for manual operation shall be positioned such that, where practicable, it can be operated from a position of safety and accessed without exposure to the hazards of passing trains or exposed electrical conductors. Within these constraints the control equipment should be sited as close to the switch rail toes as is practicable. 6 Equipment Performance Requirements As far as practicable, all failure modes which present an unacceptable risk to train movements shall result in a loss of correspondence. Point operation and detection mechanisms shall be designed to operate safely and reliably under all credible operating conditions of vibration, temperature, precipitation and environmental pollution without specific adjustment. The operation time of all point operating mechanisms shall be compatible with the signalling system. 7 New and Redundant Points Points, whether facing or trailing, shall be installed so that there is the minimum delay in connecting them to the signal box or ground 6 R A I L T R A C K

9 Date July1997 Page 7 of 8 frame. Similarly, redundant points shall be removed as quickly as possible after disconnection from the signal box or ground frame. The interval between installation and connection or disconnection and removal shall not normally exceed six months. Where points are not connected to the control system (e.g. as a result of alterations), Railtrack shall make arrangements for the integrity of the railway to be maintained. R A I L T R A C K 7

10 Date July 1997 Page 8 of 8 References GK/RT0009 Identification of Signalling and Related Equipment GK/RT0039 Semaphore and Mechanical Signalling GK/RT0060 Interlocking Principles GK/RT0061 Shunters Releases. Ground Frames, Switch Panels and Gate Boxes GK/RT0065 Train Operated Points 8 R A I L T R A C K