1、Std. ref. : EN 50126Project Nr. : 4675dav :Tech. Body: TC9XLanguage : ETitle : Railway applications - The specification and demonstration of Reliability, Availability, Maintainability and Safety (RAMS)Software : Word97Remarks : n/aPage 2EN 50126:1999ForewordThis European Standard was prepared by the
2、 Technical Committee CENELEC TC 9X, Electrical and electronic applications in railways.The text of the draft was submitted to the formal vote and was approved by CENELEC as EN 50126 on 1998-10-01.The following dates were fixed: latest date by which the EN has to be implementedat national level by pu
3、blication of an identicalnational standard or by endorsement (dop) 2000-04-01 latest date by which the national standards conflictingwith the EN have to be withdrawn (dow) 2000-04-01Annexes designated “normative” are part of the body of the standard. Annexes designated “informative” are given for in
4、formation only. In this standard, annexes A to E are informative._Page 3EN 50126:1999ContentPageIntroduction 51 Scope62 Normative references73 Definitions .84 Railway RAMS 114.1 Introduction 114.2 Railway RAMS and quality of service 114.3 Elements of railway RAMS 124.4 Factors influencing railway RA
5、MS .144.4.1 General 144.4.2 Categories of factors144.4.3 Management of factors 184.5 The means to achieve railway RAMS requirements 194.5.1 General 194.5.2 RAMS specification:.194.6 Risk 204.6.1 Risk concept:204.6.2 Risk analysis: .204.6.3 Risk evaluation and acceptance 214.7 Safety integrity .224.8
6、 Fail-safe concept245 Management of railway RAMS .255.1 General 255.2 System lifecycle .255.3 Application of this standard316 RAMS lifecycle346.1 Phase 1: Concept 346.2 Phase 2: System definition and application conditions 366.3 Phase 3: Risk analysis.396.4 Phase 4: System requirements416.5 Phase 5:
7、 Apportionment of system requirements 456.6 Phase 6: Design and implementation 476.7 Phase 7: Manufacturing .506.8 Phase 8: Installation.526.9 Phase 9: System validation (including safety acceptance and commissioning) 546.10 Phase 10: System acceptance.566.11 Phase 11: Operation and maintenance576.1
8、2 Phase 12: Performance monitoring586.13 Phase 13: Modification and retrofit.596.14 Phase 14: Decommissioning and disposal 60Annex A (informative) Outline of RAMS specification - example .61Annex B (informative) RAMS programme66Annex C (informative) Examples of parameters for railway.71Annex D (info
9、rmative) Examples of some risk acceptance principles73Annex E (informative) Responsibilities within the RAMS process throughout the lifecycle .76PagePage 4EN 50126:1999FiguresFigure 1: Quality of Service and Railway RAMS12Figure 2: Inter-relation of Railway RAMS elements .12Figure 3: Effects of Fail
10、ures Within a System 13Figure 4: Influences on RAMS .14Figure 5: Factors Influencing Railway RAMS.16Figure 6: Example of a Cause/Effect Diagram.18Figure 7: Certified Products in Safety Systems23Figure 8: System Lifecycle .26Figure 9: Project Phase Related Tasks (Sheet 1 of 2).27Figure 9: Project Pha
11、se Related Tasks (Sheet 2 of 2).28Figure 10: The V Representation.30Figure 11: Verification and Validation 31Figure 12:RAMS Eng. and Managt Implemented within a System Realisation Process.33TablesTable 1: RAM Failure Categories19Table 2: Frequency of Occurrence of Hazardous Events .20Table 3: Hazard
12、 Severity Level.21Table 4: Frequency - Consequence Matrix.21Table 5: Qualitative Risk Categories.22Table 6: Typical Example of Risk Evaluation and Acceptance .22Table B.1: Example of a Basic RAMS Programme Outline .67Table C.1: Examples of Reliability Parameters71Table C.2: Examples of Maintainabili
13、ty Parameters 71Table C.3: Examples of Availability Parameters 72Table C.4: Examples of Logistic Support Parameters .72Table C.5: Examples of Safety Performance Parameters .72Page 5EN 50126:1999IntroductionThis European Standard provides Railway Authorities and the railway support industry, througho
14、ut the European Union, with a process which will enable the implementation of a consistent approach to the management of reliability, availability, maintainability and safety, denoted by the acronym RAMS. Processes for the specification and demonstration of RAMS requirements are cornerstones of this
15、 standard. This European Standard aims to promote a common understanding and approach to the management of RAMS.This European Standard can be applied systematically by a railway authority and railway support industry, throughout all phases of the lifecycle of a railway application, to develop railwa
16、y specific RAMS requirements and to achieve compliance with these requirements. The systems-level approach defined by this European Standard facilitates assessment of the RAMS interactions between elements of complex railway applications.This European Standard promotes co-operation between a railway
17、 authority and railway support industry, within a variety of procurement strategies, in the achievement of an optimal combination of RAMS and cost for railway applications. Adoption of this European Standard will support the principles of the European Single Market and facilitate European railway in
18、ter-operability.The process defined by this European Standard assumes that railway authorities and railway support industry have business-level policies addressing Quality, Performance and Safety. The approach defined in this standard is consistent with the application of quality management requirem
19、ents contained within the ISO 9000 series of International standards.Page 6EN 50126:19991 Scope1.1 This European Standard: defines RAMS in terms of reliability, availability, maintainability and safety and their interaction; defines a process, based on the system lifecycle and tasks within it, for m
20、anaging RAMS; enables conflicts between RAMS elements to be controlled and managed effectively; defines a systematic process for specifying requirements for RAMS and demonstrating that these requirements are achieved; addresses railway specifics; does not define RAMS targets, quantities, requirement
21、s or solutions for specific railway applications; does not specify requirements for ensuring system security; does not define rules or processes pertaining to the certification of railway products against the requirements of this standard; does not define an approval process by the safety regulatory
22、 authority.1.2. This European Standard is applicable: to the specification and demonstration of RAMS for all railway applications and at all levels of such an application, as appropriate, from complete railway routes to major systems within a railway route, and to individual and combined sub-systems
23、 and components within these major systems, including those containing software; in particular: to new systems; to new systems integrated into existing systems in operation prior to the creation of this standard, although it is not generally applicable to other aspects of the existing system; to mod
24、ifications of existing systems in operation prior to the creation of this standard, although it is not generally applicable to other aspects of the existing system. at all relevant phases of the lifecycle of an application; for use by Railway Authorities and the railway support industry.NOTE: Guidan
25、ce on the applicability is given in the requirements of this standard.Page 7EN 50126:19992 Normative referencesThis European Standard incorporates by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text and the pub
26、lications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this standard only when incorporated in it by amendment or revision. For undated references, the latest edition of the publication referred to applies.EN ISO 9001 1994 Qu
27、ality systems Model for quality assurance in design, development, production, installation and servicingEN ISO 9002 1994 Quality systems Model for quality assurance in production, installation and servicingEN ISO 9003 1994 Quality systems Model for quality assurance in final inspection and testEN 50
28、128 (*) Railway applications - Software for railway control and protection systemsENV 50129 1998 Railway applications - Safety related electronic systems for signallingIEC 60050(191) 1990 International Electrotechnical VocabularyChapter 191: Dependability and quality of serviceIEC 61508 series Funct
29、ional safety of electrical/electronic/programmable electronic safety-related systems_(*) In preparationPage 8EN 50126:19993 DefinitionsFor the purposes of this standard, the following definitions apply.3.1 apportionment: A process whereby the RAMS elements for a system are sub-divided between the va
30、rious items which comprise the system to provide individual targets.3.2 assessment: The undertaking of an investigation in order to arrive at a judgement, based on evidence, of the suitability of a product.3.3 audit: A systematic and independent examination to determine whether the procedures specif
31、ic to the requirements of a product comply with the planned arrangements, are implemented effectively and are suitable to achieve the specified objectives.3.4 availability: The ability of a product to be in a state to perform a required function under given conditions at a given instant of time or o
32、ver a given time interval assuming that the required external resources are provided.3.5 commissioning: A collective term for the activities undertaken to prepare a system or product prior to demonstrating that it meets its specified requirements.3.6 common cause failure: A failure which is the resu
33、lt of an event(s) which causes a coincidence of failure states of two or more components leading to a system failing to perform its required function.3.7 compliance: A demonstration that a characteristic or property of a product satisfies the stated requirements.3.8 configuration management: A disci
34、pline applying technical and administrative direction and surveillance to identify and document the functional and physical characteristics of a configuration item, control change to those characteristics, record and report change processing and implementation status and verify compliance with speci
35、fied requirements.3.9 corrective maintenance: The maintenance carried out after fault recognition and intended to put a product into a state in which it can perform a required function.3.10 dependent failure: The failure of a set of events, the probability of which cannot be expressed as the simple
36、product of the unconditional probabilities of the individual events.3.11 down time: The time interval during which a product is in a down state. (IEC 60050(191)3.12 failure cause: The circumstances during design, manufacture or use which have led to a failure. (IEC 60050(191)3.13 failure mode: The p
37、redicted or observed results of a failure cause on a stated item in relation to the operating conditions at the time of the failure.3.14 failure rate: The limit, if this exists, of the ratio of the conditional probability that the instant of time, T, of a failure of a product falls within a given ti
38、me interval (t, t+t) and the length of this interval, t, when t tends towards zero, given that the item is in an up state at the start of the time interval.3.15 fault mode: One of the possible states of a faulty product for a given required function. (IEC 60050(191)3.16 fault tree analysis: An analy
39、sis to determine which fault modes of the product, sub-products or external events, or combinations thereof, may result in a stated fault mode of the product, presented in the form of a fault tree.3.17 hazard: A physical situation with a potential for human injury.3.18 hazard log: The document in wh
40、ich all safety management activities, hazards identified, decisions made and solutions adopted are recorded or referenced. Also known as a ”Safety Log”. (ENV 50129)Page 9EN 50126:19993.19 logistic support: The overall resources which are arranged and organised in order to operate and maintain the sy
41、stem at the specified availability level at the required lifecycle cost.3.20 maintainability: The probability that a given active maintenance action, for an item under given conditions of use can be carried out within a stated time interval when the maintenance is performed under stated conditions a
42、nd using stated procedures and resources. (IEC 60050(191)3.21 maintenance: The combination of all technical and administrative actions, including supervision actions, intended to retain a product in, or restore it to, a state in which it can perform a required function. (IEC 60050(191)3.22 maintenan
43、ce policy: A description of the inter-relationship between the maintenance echelons, the indenture levels and the levels of maintenance to be applied for the maintenance of an item. (IEC 60050(191)3.23 mission: An objective description of the fundamental task performed by a system.3.24 mission profi
44、le: Outline of the expected range and variation in the mission with respect to parameters such as time, loading, speed, distance, stops, tunnels, etc., in the operational phases of the lifecycle.3.25 preventive maintenance: The maintenance carried out at pre-determined intervals or according to pres
45、cribed criteria and intended to reduce the probability of failure or the degradation of the functioning of an item. (IEC 60050(191)3.26 railway authority: The body with the overall accountability to a Regulator for operating a railway system.NOTE: Railway authority accountabilities for the overall s
46、ystem or its parts and lifecycle activities are sometimes split between one or more bodies or entities. For example: the owner(s) of one or more parts of the system assets and their purchasing agents; the operator of the system; the maintainer(s) of one or more parts of the system; etc.Such splits a
47、re based on either statutory instruments or contractual agreements. Such responsibilities should therefore be clearly stated at the earliest stages of a system lifecycle.3.27 railway support industry: Generic term denoting supplier(s) of complete railway systems, their sub-systems or component parts
48、.3.28 RAM programme: A documented set of time scheduled activities, resources and events serving to implement the organisational structure, responsibilities, procedures, activities, capabilities and resources that together ensure that an item will satisfy given RAM requirements relevant to a given c
49、ontract or project. (IEC 60050(191).3.29 RAMS: An acronym meaning a combination of Reliability, Availability, Maintainability and Safety.3.30 reliability: The probability that an item can perform a required function under given conditions for a given time interval (t1, t2). (IEC 60050(191)3.31 reliability growth: A condition characterised by a progressive improvement of a reliability performance measure of an item with time. (IEC 60050(191)3.32 repair: That part of a corrective maintenance in which manual actions are p
