Risk Management of Rail Vehicle Axle Bearings

Transcription

1 Railway Group Standard Risk Management of Rail Vehicle Axle Bearings Synopsis This Railway Group Standard mandates that there shall be riskbased processes to minimise and detect failures of rail vehicle axle bearings. 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 Euston Road London Copyright 1996 Railtrack PLC

2 This page is intentionally blank.

3 Railway Group Standard Page 1 of 10 Contents Section Description Page Part A Issue record 2 Responsibilities and distribution 2 Implementation 2 Health & safety responsibilities 2 Supply 2 Part B 1 Purpose 3 2 Scope 3 3 Definitions 3 4 Principle 3 5 Introduction 4 6 Requirements 4 7 Action in the event of an alarm 5 8 Records 5 Appendices A Background to control of overheating axle bearing risk 6 B Risk assessments for overheating axle bearing detection 8 References 10 R A I L T R A C K 1

4 Railway Group Standard Page 2 of 10 Withdrawn Document Part A Issue record This standard will be updated when necessary by distribution of a complete replacement.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 April 96 Original document. Responsibilities and Controlled copies of this standard shall be complied with by all people distribution who are responsible for : specifying the design, construction and maintenance of rail vehicles; deciding which routes or rail vehicles require hot axlebox detectors. Implementation The provisions of this Railway Group Standard are mandatory and compliance is required for new or modified vehicles and line side equipment from 3 August1996. Retrospective action is not required. Health and safety responsibilities In authorising this Standard, Railtrack PLC makes no warranties, express or implied, that compliance with all or any 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. Supply 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. 2 R A I L T R A C K

5 Railway Group Standard Page 3 of 10 Part B 1 Purpose The purpose of this Railway Group Standard is to define the measures to control the risks posed by overheating axle bearings on rail vehicles, and to identify methods by which these risks can be controlled. 2 Scope The contents of this standard apply to: all rail vehicles that operate on Railtrack controlled infrastructure, except track maintenance machines and road/rail vehicles operated solely in accordance with Rule Book Appendices 14 and 14a; railway routes within Railtrack controlled infrastructure. 3 Definitions Axle bearing Bearing on a rail vehicle axle that transmits a proportion of the weight of the vehicle directly to the wheelset. Inside bearing An axle bearing located between the adjacent wheel and the centre of the axle shaft. Hot axlebox An axle bearing overheated, or in the process of overheating, as a result of failure of or damage to the bearing. Hot Axlebox Detector (HABD) A line side device that detects when an axlebox of a passing rail vehicle is overheating, and triggers an alarm. Passenger Any person, whether fare-paying or not (but excluding train crew) for whom accommodation is provided for riding in a train. Railtrack Railtrack PLC, the infrastructure controller of the mainland railway network, operating under a licence issued by the Secretary of State for Transport. ALARP As low as reasonably practicable. 4 Principle Trains shall not operate over Railtrack controlled infrastructure without there being means of controlling the risks from overheating axle bearings. R A I L T R A C K 3

6 Railway Group Standard Page 4 of 10 Withdrawn Document 5 Introduction 5.1 The risk A defective axle bearing on a rail vehicle can lead to the overheating of that bearing. If an overheated bearing is not detected in time, catastrophic failure of the bearing and axle end may result. Axle end failure can have serious, hazardous consequences such as derailment of the vehicle along with the possibility of ignition of inflammable material. (See background information in Appendix A.) 5.2 Controlling the risk There shall be processes in place to manage axle bearing design, construction, testing, operation, maintenance and repair. These processes shall be sufficient to control the risk of axle bearing failure Experience shows that, despite the control measures identified in sub-paragraph 5.2.1, there remains a significant residual risk which must be mitigated by additional control measures. To achieve this mitigation, present practice is to install means for detection of overheating axle bearings, either at the line side or on the vehicles Changes to rail vehicles or to railway route characteristics may import additional risk. Train operators and Railtrack shall have processes in place to manage these changes. These processes should follow the guidance given in the code of practice GA/RC Examples of methods by which an overheating axle bearing can be detected are described in Appendix A. 6 Requirements 6.1 The safety performance of axle bearings in operation shall be jointly monitored and reviewed against targets agreed between the train operator and Railtrack (see GM/RT2250). The targets shall reflect the level of risk identified, based on the ALARP principle. 6.2 When changes are proposed to rail vehicles that the train operator proposes to run on Railtrack controlled infrastructure, the train operator shall identify the risk in conjunction with Railtrack. 6.3 There shall be processes in place to manage axle bearing design, construction, testing, operation, maintenance, overhaul and repair. The train operator shall ensure that these processes are sufficient to control the risk of axle bearing failure (see GM/RT2020, 2026, 2027 and 2030, and GM/TT0081 and 0120). 6.4 There shall be equipment or processes, agreed between the train operator and Railtrack, for identifying overheating axle bearings in sufficient time to permit mitigating action to be taken. Where this requirement is met by the provision of lineside h.ot axlebox detection equipment, it shall comply with. 4 R A I L T R A C K

7 Railway Group Standard Page 5 of There shall be a method, agreed between the train operator and Railtrack, for dealing with a rail vehicle that has been identified as having an overheated axle bearing (see GO/OP0006 and GO/RT3207). 6.6 Change to Railtrack controlled infrastructure related to hot axlebox detection systems shall be advised by Railtrack to the train operators, prior to introduction of the change. Railtrack shall ensure that a risk assessment of the change is undertaken in conjunction with the train operators, and appropriate action agreed. 6.7 Change to a method of detecting an overheated axle bearing shall be advised by the party proposing the change to the other party, prior to introduction. A risk assessment of the change shall be undertaken jointly and appropriate action agreed. 6.8 Where necessary, a rail vehicle owner may undertake the responsibilities assigned to a train operator in this standard. Any such delegation must be documented. (Please also refer to GM/RT2004). 6.9 Appendix B outlines means by which risk assessments of rail vehicles and routes may be carried out. 7 Action in the event of 7.1 The train operator and Railtrack shall have agreed procedures in an alarm place to deal with any rail vehicle identified as having an overheating axle bearing so that any potential risk from the overheating axle bearing is minimised. 7.2 The train operator and Railtrack shall have agreed procedures in place to ensure that a rail vehicle identified as having an overheating axle bearing is prevented from re-entering service until a competent person has specified the actions to be taken to make the vehicle safe and those actions have been carried out. 8 Records 8.1 Train operators and infrastructure controllers shall keep records of all alarms triggered by both on-vehicle systems and line side systems, including any detections obtained by manual observation or other methods. 8.2 Train operators shall monitor and record overheated axle bearings as part of their safety performance monitoring and defect reporting (see GM/RT2250). 8.3 To facilitate the joint risk assessment specified in paragraph 6.1, the train operator shall make available to Railtrack information on the safety performance of its axle bearings and Railtrack shall make available to train operators information regarding the operational reliability of line side equipment. 8.4 Records of overheated axle bearings shall be made available for the use of any relevant body having reasonable safety grounds for accessing them. 8.5 Records shall be maintained for the timescales laid down in GM/TT0110. R A I L T R A C K 5

8 Railway Group Standard Page 6 of 10 Withdrawn Document Appendix A This appendix is for information only. Background to control of overheating axle bearing risk A.1 Introduction Failed axle bearings on trains create a hazard to the safe operation of the railway. An indication that a bearing is about to fail is a rise in the heat generated by the bearing. Failed bearings can be detected through this overheating. On principal railway routes that are signalled from remote signalling centres or cabins it is not possible for railway personnel reliably to observe passing trains to detect the presence of overheating axle bearings. When axle bearings fail, there is a risk of the axle journal being severely damaged and the adjoining wheel becoming unloaded, potentially leading to the vehicle derailing. There are two, distinctive modes of bearing failure: gradual, for example due to abnormal wear, where the failure occurs over a long distance and causes the bearing gradually to overheat. World wide experience shows that the risk can be reduced to a reasonable level by siting hot axlebox detectors (HABDs) at the line side at intervals of between 20 and 30 miles; rapid, where the bearing suddenly endures severe internal damage, for example due to serious lubrication failure or mechanical component collapse. In such cases, failure and potential derailment can occur within a very short time span. A.2 Preventing axle The design, manufacture, overhaul, maintenance and repair of rail vehicle axle bearing failures bearings is critical to the safety prevention of bearing failure. A suite of Railway Group Standards addresses these issues and mandates actions on all parties involved in these activities (see References). Adherence to the requirements of this suite of standards is an essential step towards reducing axle bearing failures. This standard addresses the residual risk when these control measures have not been totally effective. A.3 On-vehicle detection Dependent on the results of risk assessments carried out in accordance with this of overheating standard, train operators and Railtrack may agree that specific rail vehicles axle bearings operating on certain routes are best protected by installing on-vehicle hot axle bearing detection. This may be because: hot axlebox detectors (HABDs) located at the line side cannot currently view all axle bearings (e.g. those that are located between the wheels, i.e. inside bearings, and other, obstructed axleboxes); line side HABDs spaced at 20 to 30 mile intervals cannot reliably detect bearings that fail rapidly (see section A.1). 6 R A I L T R A C K

9 Railway Group Standard Page 7 of 10 Railway Group Standard GM/RT2243 therefore includes requirements for rail vehicles to be provided with an on-vehicle system for detection of overheating axle bearings where the risk of not doing so is unacceptable. A.4 Detection of over- Dependent on the results of risk assessments carried out in accordance with this heating axle bearings standard, train operators and Railtrack may agree that specific rail vehicles from the line side operating on certain routes are best protected by installing line side HABDs (see GO/RT3207 for criteria for siting of HABDs). A line side HABD can alert a signaller that a train has passed with an overheating axle bearing. Arrangements can then be made to stop the train for examination. Railway Group Standard GO/OP0006 mandates the operating procedures for examination of the train. Railway Group Standard GM/RT2243 mandates parameters for successful detection of overheating axle bearings. [NB: There is considerable further potential to collate and analyse the measurements recorded by the HABDs and so develop a history of axle bearing performance. This potential can be realised effectively when supported by technology such as a form of automatic vehicle recognition (AVR).] On routes where there are sufficient personnel at the line side (e.g. signallers) and the risk is considered to be tolerable, an acceptable method for detection of failing axle bearings may be by manual observation (sight and sound) of passing trains. A.5 Route acceptance The presence or absence of hot axlebox detection equipment at the line of rail vehicles side or on rail vehicles are factors to be taken into account in the route acceptance of rail vehicles (GO/RT3270). A.6 Safety cases for Code of practice GA/RC6605 recommends that a safety case is prepared and detection of overheating considered whenever change is proposed that could affect the safety of Railtrack axle bearings controlled infrastructure. This safety case includes the assessment of risks, and is a recommended approach to implementing the requirements of this standard (). R A I L T R A C K 7

10 Railway Group Standard Page 8 of 10 Withdrawn Document Appendix B This appendix is for information only. Risk assessments for overheating axle bearing detection B.1 Assessment of B.1.1 The train operator, in conjunction with Railtrack, should assess each rail rail vehicles vehicle type to determine the risk to the railway of not installing on-vehicle hot axle bearing detection. Targets for axle bearing safety performance should be set, and performance monitored against them. Joint risk assessment of a rail vehicle type should be undertaken: when rail vehicles are submitted to an infrastructure controller for route acceptance (see GO/RT3270); * if there is any relevant engineering change to a rail vehicle; * if the use of a rail vehicle changes in a significant and relevant way (e.g. it is proposed to carry dangerous goods); * if traffic speeds increase significantly; * if axle bearing loadings increase significantly; * if the infrastructure controller proposes changes to the characteristics of a route (e.g. withdrawal of line side HABDs or signal box closures); * if the routes on which a rail vehicle operates are changed (e.g. different route characteristics, line side HABDs proposed to be removed); * if other changes affecting risk occur. B.1.2 The risk assessment in B.1.1 should take account of, for example: * potential axle bearing life; * mean time between failures of axle bearings; * the presence of passengers on the rail vehicle; * the use of inside bearings; * the presence of shrouding or other obstruction to the view of a line side HABD; * traffic type (e.g. dangerous goods); * environmental consequence of derailment or damage (e.g. risk to built-up areas or line side installations); * the presence or otherwise of line side HABDs. B.1.3 The infrastructure controller should co-operate reasonably with train operators when requested by providing relevant information on the route characteristics and design and installation of HABDs to support the risk assessments. B.1.4 If the train operator and Railtrack determine that the risk of not installing on-vehicle hot axle bearing detection is unacceptable, either on-vehicle hot axle bearing detection should be installed in accordance with the requirements of GM/RT2243; or 8 R A I L T R A C K

11 Railway Group Standard Page 9 of 10 the train operator should agree with the infrastructure controller an alternative solution. B.2 Assessment of routes B.2.1 The infrastructure controller, in conjunction with each train operator, should ensure that each railway route is assessed to determine the risk to the railway of not installing line side hot axlebox detectors. This joint risk assessment of a route should be undertaken: * if traffic frequencies increase significantly; * if rail vehicle types change significantly; * if traffic speeds increase significantly; * if changes are proposed to route management (e.g. signal box closures, changes to HABD installations); * if other changes affecting risk occur. B.2.2 The risk assessment in B.2.1 should take account of, for example: * rail vehicle types encountered on the route (including whether on-vehicle hot axle bearing detection is fitted to them); * train speeds; * traffic type (e.g. dangerous goods); * traffic density; * risk of injury or fatality to people; * route characteristics (e.g. presence, position and spacing of manned signal boxes; single or multiple track); * environmental consequence of rail vehicle derailment or damage (e.g. risk to built-up areas or line side installations); * types of HABDs; * known performance of HABDs. B.2.3 Train operators should co-operate reasonably with infrastructure controllers when requested to support the risk assessments by providing relevant information on the design and the safety performance of their rail vehicles. B.2.4 If the infrastructure controller and train operators determine that the risk of not installing line side HABDs is unacceptable, either line side HABDs should be installed on the route in accordance with the requirements of GM/RT2243; or the infrastructure controller should agree with the train operator(s) an alternative solution. B.3 Responsibilities: Rail vehicle owner Where necessary, a rail vehicle owner may undertake the responsibilities assigned to the train operator in Appendix B of this standard. This may be when rail vehicles are not yet assigned to an operator, or when several operators are involved in their haulage (e.g. wagons under private wagon registration agreements). R A I L T R A C K 9

12 Railway Group Standard Page 10 of 10 Withdrawn Document References GA/RC6605 Safety Assurance in the Management of Change GM/RT2004 Rail Vehicle Maintenance and Overhaul Policy GM/RT2020 Policy for the Engineering of Wheelsets used on Railtrack Lines GM/RT2026 Wheelsets: In Service Safety and Maintenance Attention GM/RT2027 Wheelsets: Off-Vehicle Repair and Overhaul GM/RT2030 Axle Bearing Maintenance and Overhaul GM/RT2243 Parameters for Hot Axlebox Detection Equipment GM/RT2250 Safety Performance Monitoring and Defect Reporting of Rail Vehicles and Plant and Machinery GM/TT0081 GM/TT0110 GM/TT0120 Wheelset Design Traction and Rolling Stock Records Wheelset Testing GO/RT3207 Hot Axlebox Detectors - Siting GO/RT3270 Route Acceptance of Rail Vehicles GO/OP0006 Hot Axlebox Detectors - Action in the Event of an Alarm - Railway Group Safety Plan 10 R A I L T R A C K