Railway Applications - The Specification and Demonstration of Reliability, Availability, Maintainability and Safety (RAMS) - Part 1: Generic RAMS Process

This part 1 of EN 50126
-   considers RAMS, understood as reliability, availability, maintainability and safety and their interaction;
-   considers the generic aspects of the RAMS life cycle. The guidance in this part can still be used in the application of specific standards;
-   defines:
-   a process, based on the system life cycle and tasks within it, for managing RAMS;
-   a systematic process, tailorable to the type and size of the system under consideration, for specifying requirements for RAMS and demonstrating that these requirements are achieved;
-   addresses railway specifics;
-   enables conflicts between RAMS elements to be controlled and managed effectively;
-   does not define:
-   RAMS targets, quantities, requirements or solutions for specific railway applications;
-   rules or processes pertaining to the certification of railway products against the requirements of this standard;
-   an approval process for the railway stakeholders.
This part 1 of EN 50126 is applicable to railway application fields, namely Command, Control and Signalling, Rolling Stock and Fixed Installations, and specifically:
-   to the specification and demonstration of RAMS for all railway applications and at all levels of such an application, as appropriate, from complete railway systems to major systems and to individual and combined subsystems and components within these major systems, including those containing software; in particular:
-   to new systems;
-   to new systems integrated into existing systems already accepted, but only to the extent and insofar as the new system with the new functionality is being integrated. It is otherwise not applicable to any unmodified aspects of the existing system;
-   as far as reasonably practicable, to modifications and extensions of existing systems already accepted, but only to the extent and insofar as existing systems are being modified. It is otherwise not applicable to any unmodified aspect of the existing system;
-   at all relevant phases of the life cycle of an application;
-   for use by railway duty holders and the railway suppliers.
It is not required to apply this standard to existing systems which remain unmodified, including those systems already compliant with any former version of EN 50126.
The process defined by this European Standard assumes that railway duty holders and railway suppliers have business-level policies addressing Quality, Performance and Safety. The approach defined in this standard is consistent with the application of quality management requirements contained within EN ISO 9001.

Bahnanwendungen - Spezifikation und Nachweis von Zuverlässigkeit, Verfügbarkeit, Instandhaltbarkeit und Sicherheit (RAMS) - Teil 1: Generischer RAMS-Prozess

Applications ferroviaires - Spécification et démonstration de la fiabilité, de la disponibilité, de la maintenabilité et de la sécurité (FDMS) - Partie 1 : Processus FMDS générique

La présente Partie 1 de l'EN 50126 :
-   définit la FDMS en termes de fiabilité, de disponibilité, de maintenabilité et de sécurité et leurs interactions ;
-   prend en considération les aspects génériques du cycle de vie FDMS. Les lignes directrices de la présente partie s'appliquent également lors de l'application de normes spécifiques ;
-   définit :
-   un processus de management de la FDMS fondé sur le cycle de vie du système et les tâches qui en font partie ;
-   un processus systématique adaptable au type et à la taille du système en cours d'examen, permettant de spécifier les exigences de la FDMS et de démontrer que ces exigences sont satisfaites ;
-   prend en compte les spécificités du domaine ferroviaire ;
-   permet de contrôler et de gérer efficacement les conflits entre les composantes de la FDMS ;
-   ne définit pas :
-   les objectifs de FDMS, ni les grandeurs, les exigences ou les solutions pour des applications ferroviaires spécifiques ;
-   les règles ou les processus de certification des produits ferroviaires vis-à-vis des exigences de la présente norme ;
-   un processus d'homologation pour les parties prenantes ferroviaires.
La présente Partie 1 de l'EN 50126 s'applique aux domaines d'application ferroviaire, à savoir Contrôle commande et Signalisation, Matériel Roulant et Installations Fixes, et spécifiquement :
-   à la spécification et à la démonstration des exigences de FDMS pour toute application ferroviaire et à tout niveau d'une telle application, selon le cas, allant des systèmes ferroviaires complets aux grands systèmes et aux sous-systèmes et équipements (individuels et combinés) de ces grands systèmes, y compris ceux qui comportent des logiciels. Elle est notamment applicable :
-   aux nouveaux systèmes ;
-   aux nouveaux systèmes intégrés dans des systèmes préexistants acceptés, mais seulement dans la mesure où, et dans la façon dont le nouveau système comprenant la nouvelle fonctionnalité y est intégré. Elle n'est sinon pas applicable aux parties inchangées du système existant ;
-   dans toute la mesure du possible, aux modifications et extensions des systèmes préexistants, mais seulement dans la mesure où, et dans la façon dont les systèmes existants sont modifiés. Elle n'est sinon pas applicable aux parties inchangées du système existant ;
-   à toutes les phases concernées du cycle de vie d'une application donnée ;
-   à l'utilisation des sociétés d'exploitation ferroviaire et des industries ferroviaires.
Il n'est pas nécessaire d'appliquer la présente norme aux systèmes existants qui ne sont pas modifiés, y compris ceux déjà conformes à toute version antérieure de l'EN 50126.
Le processus défini par la présente Norme européenne part du principe que les sociétés d'exploitation et les industries ferroviaires ont développé au niveau de l'entreprise des politiques de Qualité, Performances et Sécurité. L'approche définie dans la présente norme est en accord avec l'application des exigences de management de la qualité de l'EN ISO 9001.

Železniške naprave - Specifikacija in prikaz zanesljivosti, razpoložljivosti, vzdrževalnosti in varnosti (RAMS) - 1. del: Generični procesi RAMS - Dopolnilo A1

General Information

Status
Not Published
Public Enquiry End Date
30-Apr-2023
Current Stage
4020 - Public enquire (PE) (Adopted Project)
Start Date
15-Feb-2023
Due Date
05-Jul-2023
Completion Date
11-May-2023

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SLOVENSKI STANDARD
SIST EN 50126-1:2018/oprA1:2023
01-april-2023
Železniške naprave - Specifikacija in prikaz zanesljivosti, razpoložljivosti,
vzdrževalnosti in varnosti (RAMS) - 1. del: Generični procesi RAMS - Dopolnilo A1
Railway Applications - The Specification and Demonstration of Reliability, Availability,
Maintainability and Safety (RAMS) - Part 1: Generic RAMS Process
Bahnanwendungen - Spezifikation und Nachweis von Zuverlässigkeit, Verfügbarkeit,
Instandhaltbarkeit und Sicherheit (RAMS) - Teil 1: Generischer RAMS-Prozess
Applications ferroviaires - Spécification et démonstration de la fiabilité, de la disponibilité,
de la maintenabilité et de la sécurité (FDMS) - Partie 1 : Processus FMDS générique
Ta slovenski standard je istoveten z: EN 50126-1:2017/prA1
ICS:
03.120.01 Kakovost na splošno Quality in general
45.020 Železniška tehnika na Railway engineering in
splošno general
SIST EN 50126-1:2018/oprA1:2023 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 50126-1:2018/oprA1:2023

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SIST EN 50126-1:2018/oprA1:2023


EUROPEAN STANDARD DRAFT
EN 50126-1:2017
NORME EUROPÉENNE

EUROPÄISCHE NORM
prA1
February 2023
ICS 29.280; 45.020 -
English Version
Railway Applications - The Specification and Demonstration of
Reliability, Availability, Maintainability and Safety (RAMS) - Part
1: Generic RAMS Process
Railway Applications - The Specification and Demonstration Bahnanwendungen - Spezifikation und Nachweis von
of Reliability, Availability, Maintainability and Safety (RAMS) Zuverlässigkeit, Verfügbarkeit, Instandhaltbarkeit und
- Part 1: Generic RAMS Process Sicherheit (RAMS) - Teil 1: Generischer RAMS-Prozess
This draft amendment prA1, if approved, will modify the European Standard EN 50126-1:2017; it is submitted to CENELEC members for
enquiry.
Deadline for CENELEC: 2023-04-28.

It has been drawn up by CLC/TC 9X.

If this draft becomes an amendment, CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which
stipulate the conditions for giving this amendment the status of a national standard without any alteration.

This draft amendment was established by CENELEC in three official versions (English, French, German).
A version in any other language made by translation under the responsibility of a CENELEC member into its own language and notified to
the CEN-CENELEC Management Centre has the same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the
Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Türkiye and the United Kingdom.

Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are aware and to
provide supporting documentation.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without notice and
shall not be referred to as a European Standard.



European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2023 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Project: 72022 Ref. No. EN 50126-1:2017/prA1 E

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SIST EN 50126-1:2018/oprA1:2023
EN 50126-1:2017/prA1:2023 (E)
Contents Page
European foreword . 3
1 Modification to references . 4
2 Modification to Clause 2, "Normative References" . 4
3 Modification to Clause 3, "Terms and definitions " . 4
4 Modification to Annex ZZ . 9

2

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SIST EN 50126-1:2018/oprA1:2023
EN 50126-1:2017/prA1:2023 (E)
European foreword
This document (EN 50126-1:2017/prA1:2023) has been prepared by Technical Committee CLC/TC 9X
“Electrical and electronic applications for railways”, the secretariat of which is held by France.
This document is currently submitted to the Enquiry.
The following dates are proposed:
• latest date by which the existence of this (doa) dor + 6 months
document has to be announced at national
level
• latest date by which this document has to be (dop) dor + 12 months
implemented at national level by publication of
an identical national standard or by
endorsement
• latest date by which the national standards (dow) dor + 36 months
conflicting with this document have to be (to be confirmed or
withdrawn modified when voting)

This document has been prepared under a Standardization Request given to CENELEC by the European
Commission and the European Free Trade Association, and supports essential requirements of EU Directive(s)
/ Regulation(s).
For relationship with EU Directive(s) / Regulation(s), see informative Annex ZZ, which is an integral part of this
document.
3

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SIST EN 50126-1:2018/oprA1:2023
EN 50126-1:2017/prA1:2023 (E)
1 Modification to references
1 1
Throughout the text replace EN 50126-2 with EN 50126-2:2017 , and EN 50126-2:2017 with EN 50126-2:2017 .
2 Modification to Clause 2, "Normative References"
Add the following text:
“The following document, in whole or in part, is normatively referenced in this document and is indispensable
for its application. For dated references, only the edition cited applies. For undated references, the latest edition
of the referenced document (including any amendments) applies.
1
EN 50126-2:2017, Railway Applications — The Specification and Demonstration of Reliability, Availability,
Maintainability and Safety (RAMS) — Part 2: Systems Approach to Safety
3 Modification to Clause 3, "Terms and definitions "
In all subclauses, replace the following text:
"[SOURCE: IEC 60050-821:FDIS2016]”
with the following text:
“[SOURCE: IEC 60050-821:2017] ”

Replace the following text:
“3.2
accident
unintended event or series of events that results in death, injury, loss of a system or service, or environmental
damage
[SOURCE: IEC 60050-821: FDIS2016, 821-12-02]”
with the following text:
“3.2
accident
unintended event or series of events that results in harm
[SOURCE: IEC 60050-821:2017, 821-12-02, modified – “that results in death, injury, loss of a system or service,
or environmental damage” has been replaced with “that results in harm]”

Replace the following text:
“3.5
audit
systematic, independent, documented process for obtaining records, statements of fact or other relevant
information and assessing them objectively to determine the extent to which specified requirements are fulfilled
Note 1 to entry: Whilst “audit” applies to management systems, “assessment” applies to conformity assessment bodies as
well as more generally.
[SOURCE: EN ISO/IEC 17000:2004, 4.4, modified – The references to other terms within ISO/IEC 17000 have
been replaced by hyperlinks to entries in the IEV.]
[SOURCE: IEC 60050-902:2013, 902-03-04]”

1
As amended by EN 50126-2:2017/prA1:2023.
4

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SIST EN 50126-1:2018/oprA1:2023
EN 50126-1:2017/prA1:2023 (E)
with the following text:
“3.5
audit
systematic, independent, documented process for obtaining records, statements of fact or other relevant
information and assessing them objectively to determine the extent to which specified requirements are fulfilled
[SOURCE: IEC 60050-902:2013, 902-03-04, modified – The note 1 to entry has been omitted]”

Replace the following text:
“3.6
availability,
ability of an item to be in a state to perform a required function under given conditions at a given instant of time
or over a given time interval, assuming that the required external resources are provided
[SOURCE: IEC 60050-821: FDIS2016, 821-05-82, modified]”
with the following text:
“3.6
availability, < for railways RAMS >
ability of an item to be in a state to perform a required function under given conditions at a given instant of time
or over a given time interval, assuming that the required external resources are provided
[SOURCE: IEC 60050-821:2017, 821-05-82, modified – “of a product” has been changed with “for railways
RAMS”]”

Replace the following text:
“3.7
basic integrity
-5 -1
integrity attribute for safety related function with a TFFR higher than (less demanding) 10 [h ] or non-safety-
related function”
with the following text:
“3.7
basic integrity
-5 -1
integrity attribute for a safety-related function with a TFFR of 10 [h ] or higher (less demanding) or for a non-
safety-related function”

Replace the following text:
“3.10
common cause failure
failures of multiple items, which would otherwise be considered independent of one another, resulting from a
single cause
[SOURCE: IEC 60050-192:2015, 192-03-18]”
with the following text:
“3.10
common cause failures, pl
failures of multiple items, which would otherwise be considered independent of one another, resulting from a
single cause
5

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SIST EN 50126-1:2018/oprA1:2023
EN 50126-1:2017/prA1:2023 (E)
Note 1 to entry: Common cause failures can also be "common mode failures".
Note 2 to entry: The potential for common cause failures reduces the effectiveness of system redundancy.
[SOURCE: IEC 60050-192:2015; 192-03-18]”

Replace the following text:
“3.21
failure,
loss of ability to perform as required
Note 1 to entry: Qualifiers, such as catastrophic, critical, major, minor, marginal and insignificant, may be used to categorize
failures according to the severity of consequences, the choice and definitions of severity criteria depending upon the field of
application.
Note 2 to entry: Qualifiers, such as misuse, mishandling and weakness, may be used to categorize failures according to the
cause of failure.
[SOURCE: IEC 60050-192:2015, 192-03-01, modified Note 1 to entry has been omitted]
[SOURCE: IEC 60050-821:FDIS2016, 821-11-19]
Note 3 to entry: "Failure" is an event, as distinguished from "fault", which is a state.”
with the following text:
“3.21
failure,
loss of ability to perform as required
Note 1 to entry: Qualifiers, such as catastrophic, critical, major, minor, marginal and insignificant, may be used to categorize
failures according to the severity of consequences, the choice and definitions of severity criteria depending upon the field of
application.
Note 2 to entry: Qualifiers, such as misuse, mishandling and weakness, may be used to categorize failures according to the
cause of failure.
Note 3 to entry: "Failure" is an event, as distinguished from "fault", which is a state.
Note 4 to entry: inability to perform a function during maintenance activities needs not to be considered.
[SOURCE: IEC 60050-821:2017, 821-11-19 modified, added Note 3 and Note 4 to entry]”

Replace the following text:
“3.23
failure rate
limit of the ratio of the conditional probability that the instant of time, T, of a failure of a product falls within a
given time interval (t, t + Δt) and the duration of this interval, Δt, when Δt tends towards zero, given that the item
is in an up state at the start of the time interval
Note 1 to entry: For applications where distance travelled or number of cycles of operation is more relevant than time then
the unit of time can be replaced by the unit of distance or cycles, as appropriate.
Note 2 to entry: The term “failure rate” is often used in the sense of “mean failure rate” defined in IEV 192-05-07.
[SOURCE: IEC 60050-821:FDIS2016]”
with the following text:
“3.23
failure rate
6

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SIST EN 50126-1:2018/oprA1:2023
EN 50126-1:2017/prA1:2023 (E)
limit of the ratio of the conditional probability that the instant of time, T, of a failure of a product falls within a
given time interval (t, t + Δt) and the duration of this interval, Δt, when Δt tends towards zero, given that the item
is in an up state at the start of the time interval
Note 1 to entry: For applications where distance travelled or number of cycles of operation is more relevant than time then
the unit of time can be replaced by the unit of distance or cycles, as appropriate.
Note 2 to entry: The term “failure rate” is often used in the sense of “mean failure rate” defined in IEV 192-05-07.
[SOURCE: IEC 60050-821:2017, 821-12-21]”

Replace the following text:
“3.25
function,
specified action or activity which can be performed by technical means and/or human beings and has a defined
output in response to a defined input
Note 1 to entry: A function can be specified or described without reference to the physical means of achieving it.
[SOURCE: IEC 60050-821:FDIS2016, 821-12-25, modified]”
with the following text:
“3.25
function,
specified action or activity which can be performed by technical means and/or human beings and has a defined
output in response to a defined input
Note 1 to entry: A function can be specified or described without reference to the physical means of achieving it.”

Replace the following text:
“3.27
generic product
product independent of applications, fulfilling pred
...

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