CLC/TR 50126-2:2007
(Main)Railway applications - The specification and demonstration of Reliability, Availability, Maintainability and Safety (RAMS) - Part 2: Guide to the application of EN 50126-1 for safety
Railway applications - The specification and demonstration of Reliability, Availability, Maintainability and Safety (RAMS) - Part 2: Guide to the application of EN 50126-1 for safety
1.1 This Technical Report provides guidance on specific issues, listed under 1.3 below, for applying the safety process requirements in EN 50126 1 to a railway system and for dealing with the safety activities during the different system life cycle phases. The guidance is applicable to all systems covered within the scope of EN 50126-1. It assumes that the users of the report are familiar with safety matters but need guidance on the application of EN 50126-1 for safety issues that are not or could not be addressed in the standard in detail. 1.2 EN 50126-1 is the top-level basic RAMS standard. This application guide, CLC/TR 50126 2 forms an informative part of EN 50126-1 dealing explicitly with safety aspects as limited by the scope defined in 1.3 below. 1.3 Limitation of scope The scope is limited to providing guidance only for the following issues related to EN 50126 1. i) Production of a top-level generic risk model for the railway system down to its major constituents (e.g., signalling, rolling stock, infrastructure, etc.) with definition of the constituents of the model and their interactions. ii) Development of a checklist of common functional hazards within a conventional railway system (including high speed lines, Light Rail Train’s, metro’s, etc.). iii) Guidance on the application of the risk acceptance principles in EN 50126-1. iv) Guidance on the application of functional safety in railway systems and qualitative assessment of tolerable risk with examples. v) Guidance for specifying relevant functional safety requirements and apportionment of safety targets to the requirements for sub-systems (e.g. for rolling stock: door systems, brake systems, etc.). vi) Guidance on the application of safety integrity level concept, through all the life cycle phases of the system. vii) Guidance on methods for combining probabilistic and deterministic means for safety demonstration. viii) Guidance on the essentials (incl. maintenance, operation, etc.) for documented evidence or proof of safety (safety case) with proposals for a common structure for such documentation.
Bahnanwendungen - Spezifikation und Nachweis der Zuverlässigkeit, Verfügbarkeit, Instandhaltbarkeit, Sicherheit (RAMS) - Teil 2: Leitfaden zur Anwendung der EN 50126-1 für Sicherheit
Applications ferroviaires - Spécification et démonstration de la fiabilité, de la disponibilité, de la maintenabilité et de la sécurité (FDMS) - Partie 2:Guide pour l’application de l’EN 50126-1 à la sécurité
Železniške naprave - Specifikacija in prikaz zanesljivosti, razpoložljivosti, vzdrževalnosti in varnosti (RAMS) - 2. del: Vodilo za uporabo EN 50126-1 za varnost
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-september-2007
Železniške naprave – Specifikacija in prikaz zanesljivosti, razpoložljivosti,
vzdrževalnosti in varnosti (RAMS) – 2. del: Vodilo za uporabo EN 50126-1 za
varnost
Railway applications - The specification and demonstration of Reliability, Availability,
Maintainability and Safety (RAMS) -- Part 2: Guide to the application of EN 50126-1 for
safety
Bahnanwendungen - Spezifikation und Nachweis der Zuverlässigkeit, Verfügbarkeit,
Instandhaltbarkeit, Sicherheit (RAMS) -- Teil 2: Leitfaden zur Anwendung der EN 50126-
1 für Sicherheit
Applications ferroviaires - Spécification et démonstration de la fiabilité, de la disponibilité,
de la maintenabilité et de la sécurité (FDMS) -- Partie 2:Guide pour l’application de l’EN
50126-1 à la sécurité
Ta slovenski standard je istoveten z: CLC/TR 50126-2:2007
ICS:
29.280 (OHNWULþQDYOHþQDRSUHPD Electric traction equipment
45.020 Železniška tehnika na Railway engineering in
splošno general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
TECHNICAL REPORT
CLC/TR 50126-2
RAPPORT TECHNIQUE
February 2007
TECHNISCHER BERICHT
ICS 45.020
English version
Railway applications -
The specification and demonstration of Reliability, Availability,
Maintainability and Safety (RAMS) -
Part 2: Guide to the application of EN 50126-1 for safety
Applications ferroviaires - Bahnanwendungen -
Spécification et démonstration Spezifikation und Nachweis
de la fiabilité, de la disponibilité, der Zuverlässigkeit, Verfügbarkeit,
de la maintenabilité Instandhaltbarkeit, Sicherheit (RAMS) -
et de la sécurité (FDMS) - Teil 2: Leitfaden zur Anwendung
Partie 2:Guide pour l’application der EN 50126-1 für Sicherheit
de l’EN 50126-1 à la sécurité
This Technical Report was approved by CENELEC on 2007-01-22.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Cyprus, the
Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.
CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
Central Secretariat: rue de Stassart 35, B - 1050 Brussels
© 2007 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. CLC/TR 50126-2:2007 E
Foreword
The European Standard EN 50126-1:1999, which was prepared jointly by the Technical Committees
CENELEC TC 9X, Electric and electronic applications for railways, and CEN TC 256, Railway applications,
under mode 4 co-operation, deals with the specification and demonstration of Reliability, Availability,
Maintainability and Safety (RAMS) for railway applications.
A guide to the application of EN 50126-1 for safety of railway systems (this CLC/TR 50126-2) and a guide for
the application to EN 50126-1 for rolling stock RAM (CLC/TR 50126-3:2006) have been produced to form
informative parts of EN 50126-1:1999. Whilst this CLC/TR 50126-2 is applicable to all railway systems,
including rolling stock, CLC/TR 50126-3:2006 is applicable to rolling stock RAM only.
This Technical Report, which was prepared by WG 8 of the Technical Committee CENELEC TC 9X, forms
an informative part of EN 50126-1:1999 and contains guidelines for the application of EN 50126-1 for the
safety of railway systems.
The text of the draft was submitted to the vote and was approved by CENELEC as CLC/TR 50126-2 on
2007-01-22.
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- 3 - CLC/TR 50126-2:2007
Contents
Introduction.8
1 Scope.9
2 References.11
3 Definitions and abbreviations.12
3.1 Guidance on the interpretation of terms and definitions used in EN 50126-1 .12
3.2 Additional safety terms.15
3.3 Abbreviations.17
4 Guidance on bodies/entities involved and concepts of system hierarchy and safety.17
4.1 Introduction.17
4.2 Bodies/entities involved in a system.18
4.3 Concepts of system hierarchy.18
4.3.1 Rail transport system environment and system hierarchy .19
4.4 Safety concepts.19
4.4.1 Hazard perspective .19
4.4.2 Risk.21
4.4.3 Risk normalising .22
5 Generic risk model for a typical railway system and check list of common functional hazards .23
5.1 Introduction.23
5.2 Generic risk model .23
5.3 Risk assessment process.24
5.3.1 Introduction.24
5.3.2 Generic process .24
5.4 Application of the risk assessment process .28
5.4.1 Depth of analysis.29
5.4.2 Preliminary hazard analysis .29
5.4.3 Qualitative and Quantitative assessment.30
5.4.4 Use of historical data.31
5.4.5 Sensitivity analysis .32
5.4.6 Risk assessment during life cycle phases.32
5.5 Check-list of common functional hazards and hazard identification .33
5.5.1 Introduction.33
5.5.2 Hazard grouping structures.34
5.5.3 Check-list of “Hazards”.35
6 Guidance on application of functional safety, functional safety requirements and SI targets,
risk apportionment and application of SILs.36
6.1 Introduction.36
6.2 Functional and technical safety.36
6.2.1 System characteristics .36
6.2.2 Railway system structure and safety requirements .37
6.2.3 Safety related functional and technical characteristics and overall system safety .37
6.3 General considerations for risk apportionment .38
6.3.1 Introduction.38
6.3.2 Approaches to apportionment of safety targets .38
6.3.3 Use of THRs.40
6.4 Guidance on the concept of SI and the application of SILs .40
6.4.1 Safety integrity.40
6.4.2 Using SI concept in the specification of safety requirements.42
6.4.3 Link between THR and SIL .46
6.4.4 Controlling random failures and systematic faults to achieve SI.46
6.4.5 Use and misuse of SILs .49
6.5 Guidance on fail-safe systems .51
6.5.1 Fail-safe concept .51
6.5.2 Designing fail-safe systems.52
7 Guidance on methods for combining probabilistic and deterministic means for safety
demonstration .54
7.1 Safety demonstration .54
7.1.1 Introduction.54
7.1.2 Detailed guidance on safety demonstration approaches.54
7.1.3 Safety qualification tests.65
7.2 Deterministic methods.65
7.3 Probabilistic methods .65
7.4 Combining deterministic and probabilistic methods.65
7.5 Methods for mechanical and mixed (mechatronic) systems.66
8 Guidance on the risk acceptance principles.67
8.1 Guidance on the application of the risk acceptance principles .67
8.1.1 Application of risk acceptance principles .67
8.1.2 The ALARP principle.68
8.1.3 The GAMAB (GAME) principle.69
8.1.4 Minimum Endogenous Mortality (MEM) safety principle (EN 50126-1, Clause D.3) .70
9 Guidance on the essentials for documented evidence or proof of safety (Safety case) .71
9.1 Introduction.71
9.2 Safety case purpose.72
9.3 Safety case scope .72
9.4 Safety case levels .72
9.5 Safety case phases .74
9.6 Safety case structure.75
9.7 Safety assessment .78
9.7.1 The scope of the safety assessor .78
9.7.2 T
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