Railway applications - Communication, signalling and processing systems - Software for railway control and protection systems

Unchanged with respect to the current edition EN 50128:2011.
Scope of the amendment:
- Alignment with EN 50126-1:2017, EN 50126-2:2017 and EN 50129:2018 together with minor corrections

Bahnanwendungen - Telekommunikationstechnik, Signaltechnik und Datenverarbeitungssysteme - Software für Eisenbahnsteuerungs- und Überwachungssysteme

Applications ferroviaires - Systèmes de signalisation, de télécommunication et de traitement - Logiciels pour systèmes de commande et de protection ferroviaire

Železniške naprave - Komunikacijski, signalni in procesni sistemi - Programska oprema za železniške krmilne in zaščitne sisteme - Dopolnilo A2

General Information

Status
Published
Public Enquiry End Date
29-Jun-2019
Publication Date
06-Sep-2020
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
10-Aug-2020
Due Date
15-Oct-2020
Completion Date
07-Sep-2020

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SLOVENSKI STANDARD
SIST EN 50128:2011/A2:2020
01-oktober-2020
Železniške naprave - Komunikacijski, signalni in procesni sistemi - Programska
oprema za železniške krmilne in zaščitne sisteme - Dopolnilo A2

Railway applications - Communication, signalling and processing systems - Software for

railway control and protection systems
Bahnanwendungen - Telekommunikationstechnik, Signaltechnik und
Datenverarbeitungssysteme - Software für Eisenbahnsteuerungs- und
Überwachungssysteme

Applications ferroviaires - Systèmes de signalisation, de télécommunication et de

traitement - Logiciels pour systèmes de commande et de protection ferroviaire
Ta slovenski standard je istoveten z: EN 50128:2011/A2:2020
ICS:
35.240.60 Uporabniške rešitve IT v IT applications in transport
prometu
45.020 Železniška tehnika na Railway engineering in
splošno general
SIST EN 50128:2011/A2:2020 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST EN 50128:2011/A2:2020
---------------------- Page: 2 ----------------------
SIST EN 50128:2011/A2:2020
EUROPEAN STANDARD EN 50128:2011/A2
NORME EUROPÉENNE
EUROPÄISCHE NORM
July 2020
ICS 35.240.60; 45.020; 93.100
English Version
Railway applications - Communication, signalling and processing
systems - Software for railway control and protection systems

Applications ferroviaires - Systèmes de signalisation, de Bahnanwendungen - Telekommunikationstechnik,

télécommunication et de traitement - Logiciels pour Signaltechnik und Datenverarbeitungssysteme - Software

systèmes de commande et de protection ferroviaire für Eisenbahnsteuerungs- und Überwachungssysteme

This amendment A2 modifies the European Standard EN 50128:2011; it was approved by CENELEC on 2020-06-22. 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.

Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC

Management Centre or to any CENELEC member.

This amendment exists 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,

Turkey and the United Kingdom.
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

© 2020 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.

Ref. No. EN 50128:2011/A2:2020 E
---------------------- Page: 3 ----------------------
SIST EN 50128:2011/A2:2020
EN 50128:2011/A2:2020 (E)
Content

European foreword ........................................................................................................................................... 3

1 General Changes....................................................................................................................................... 4

2 Modification to the Introduction .............................................................................................................. 4

3 Modification to the Scope ........................................................................................................................ 4

4 Modification to Clause 2, Normative references .................................................................................... 4

5 Modifications to 3.1, Terms and definitions ........................................................................................... 5

6 Modifications to Clause 4, Objectives, conformance and software safety integrity levels .............. 6

7 Modifications to Clause 5, Software management and organization .................................................. 7

8 Modifications to 6.2, Software verification ............................................................................................. 7

9 Modifications to 6.3, Software validation ............................................................................................... 7

10 Modifications to 6.4, Software assessment ........................................................................................... 7

11 Modifications to 6.5, Software quality assurance .................................................................................. 8

12 Modifications to 6.7, Support tools and languages............................................................................... 8

13 Modifications to Clause 7, Generic software development .................................................................. 9

14 Modifications to Clause 8, Development of application data or algorithms: systems

configured by application data or algorithms ........................................................................................ 9

15 Modifications to Clause 9, Software deployment and maintenance ................................................. 10

16 Modifications to Annex A, Criteria for the Selection of Techniques and Measures ........................ 11

17 Modifications to Annex C ....................................................................................................................... 14

---------------------- Page: 4 ----------------------
SIST EN 50128:2011/A2:2020
EN 50128:2011/A2:2020 (E)
European foreword

This document (EN 50128:2011/A2:2020) has been prepared by SC 9XA, “Communication, signalling and

processing systems”, of Technical Committee CENELEC TC 9X, “Electrical and electronic applications for

railways”.
The following dates are fixed:
• latest date by which this document has to be (dop) 2021-06-22
implemented at national level by publication of
an identical national standard or by
endorsement
• latest date by which the national standards (dow) 2023-06-22
conflicting with this document have to be
withdrawn

The EN 50128:2011 standard was amended to align with EN 50126-1:2017, EN 50126-2:2017 and

EN 50129:2018. In addition, some technical mistakes were corrected and some clarifications were added.

This European Standard should be read in conjunction with EN 50126-1:2017 “Railway applications –

The specification and demonstration of Reliability, Availability, Maintainability and Safety (RAMS) – Part 1:

Generic RAMS Process”, EN 50126-2:2017 “Railway applications – The specification and demonstration of

Reliability, Availability, Maintainability and Safety (RAMS) – Part 2: Systems Approach to Safety” and

EN 50129:2018 “Railway applications – Communication, signalling and processing systems – Safety related

electronic systems for signalling”.
---------------------- Page: 5 ----------------------
SIST EN 50128:2011/A2:2020
EN 50128:2011/A2:2020 (E)
1 General Changes

All occurrences of SIL 0 within EN 50128:2011 are replaced with Basic Integrity (EN 50126-1:2017, 3.7).

All occurrences of safety function(s) are replaced with safety-related function(s).

Use of the term “EN 50126-1” is replaced by “EN 50126-1 and EN 50126-2”.

The term “assessment” in the standard means “independent safety assessment” as per definition of

EN 50126-1:2017, 3.33.

All statements qualified by the words “software safety integrity level” are applicable also to Basic Integrity.

2 Modification to the Introduction
The following paragraph is added at the end of the Introduction:

This European Standard does not specify the requirements for the development, implementation,

maintenance and/or operation of security policies or security services needed to meet security requirements

that may be needed by the safety-related system. IT security can affect not only the operation but also the

functional safety of a system. For IT security, appropriate IT security standards should be applied.

NOTE IEC/ISO standards that address IT security in depth are ISO 27000 series, ISO/IEC TR 19791 and the

IEC 62443 series.
3 Modification to the Scope
The following subclause 1.10 is added:

1.10 For the development of User Programmable Integrated Circuits (e.g. FPGA and CPLD) guidance is

provided in EN 50129:2018, Annex F.
4 Modification to Clause 2, Normative references
Replace the list of normative references by the following:

EN 50126-1:2017, Railway applications – The specification and demonstration of Reliability, Availability,

Maintainability and Safety (RAMS) – Part 1: Generic RAMS Process

EN 50126-2:2017, Railway applications – The specification and demonstration of Reliability, Availability,

Maintainability and Safety (RAMS) – Part 2: Systems Approach to Safety

EN 50129:2018, Railway applications – Communication, signalling and processing systems – Safety related

electronic systems for signalling
EN ISO 9000:2015, Quality management systems – Fundamentals and vocabulary
EN ISO 9001:2015, Quality management systems – Requirements

ISO/IEC 90003:2014, Software engineering – Guidelines for the application of ISO 9001 to computer

software

ISO/IEC 25000 series, Systems and software engineering – Systems and software Quality Requirements

and Evaluation
---------------------- Page: 6 ----------------------
SIST EN 50128:2011/A2:2020
EN 50128:2011/A2:2020 (E)
5 Modifications to 3.1, Terms and definitions
Replace 3.1.9 (deleted) with:
3.1.51
error,

defect, mistake or inaccuracy that could result in a deviation from the intended performance or behaviour of

the software

Note 1 to entry: definition is derived from EN 50126-1:2017, 3.20 and adapted for software (caused by systematic fault,

e.g. human error, in line with EN 50126-1:2017 3.20 Note 2).
3.1.52
fault
abnormal condition that could lead to an error in a system
Note 1 to entry: A fault in software is systematic.

[SOURCE: IEC 60050-821:2017, 821-11-20, modified – The note 1 to entry has been modified.]

Replace 3.1.10 with:
3.1.10
failure,
loss of ability to perform as required

Note 1 to entry: “Failure” is an event, as distinguished from “fault”, which is a state.

[SOURCE: IEC 60050-821:2017, 821-11-19, modified – The notes 1 and 2 have been omitted. A new note 1

to entry has been added.]
Replace 3.1.17 with:
3.1.17
pre-existing software
software developed prior to the application currently in question

Note 1 to entry: This includes commercial off-the-shelf software, open-source software and software previously

developed but not in accordance with this European Standard.

[SOURCE: EN 50126-1:2017, 3.43, modified – The end of the definition has been moved to the note 1 to

entry.]
Definition 3.1.26 replaced by:
3.1.26
risk,

combination of expected frequency of loss and the expected degree of severity of that loss

[SOURCE: EN 50126-1:2017, 3.57]
Definition 3.1.27 replaced by:
3.1.27
safety
freedom from unacceptable risk
[SOURCE: IEC 60050-903:2013, 903-01-19]
Definition 3.1.28 replaced by:
3.1.28
safety authority

body responsible for delivering the authorization for the operation of the safety-related system

[SOURCE: IEC 60050-821:2017, 821-12-52]
Remove the term 3.1.29 and its definition (see also General Changes).
Definition 3.1.30 replaced by:
---------------------- Page: 7 ----------------------
SIST EN 50128:2011/A2:2020
EN 50128:2011/A2:2020 (E)
3.1.30
safety-related software
software which performs safety-related functions

[SOURCE: IEC 60050-821:2017, 821-12-60, modified – “safety functions” has been replaced with “safety-

related functions”.]
Definition 3.1.46 replaced by:
3.1.46
validation

confirmation, through the provision of objective evidence, that the requirements for a specific intended use or

application have been fulfilled

Note 1 to entry: The term “validated” is used to designate the corresponding status.

Note 2 to entry: The use conditions for validation can be real or simulated.

Note 3 to entry: In design and development, validation concerns the process of examining an item to determine

conformity with user needs.
Note 4 to entry: intentionally deleted

Note 5 to entry: Multiple validations can be carried out if there are different intended uses.

[SOURCE: IEC 60050-192:2015, 192-01-18, modified – The note 4 is not relevant for software]

Definition 3.1.48 replaced by:
3.1.48
verification

confirmation, through the provision of objective evidence, that specified requirements have been fulfilled

Note 1 to entry: The term “verified” is used to designate the corresponding status.

Note 2 to entry: Design verification is the application of tests and appraisals to assess conformity of a design to the

specified requirement.

Note 3 to entry: Verification is conducted at various life cycle phases of development, examining the system and its

constituents to determine conformity to the requirements specified at the beginning of that life cycle phase.

[SOURCE: IEC 60050-192:2015, 192-01-17, modified – The note 3 to entry has been modified.]

Add the following 3.1.50 (in line with EN 50126-1):
3.1.50
safety-related
carries responsibility for safety
[SOURCE: IEC 60050-821:2017, 821-01-73]

6 Modifications to Clause 4, Objectives, conformance and software safety integrity

levels
4.4 is replaced by:

4.4 At least the Basic Integrity requirements of this European Standard shall be fulfilled for the software part

of functions that have a safety impact below SIL 1.

NOTE Basic Integrity requirements can also be used for development of non safety-related software.

---------------------- Page: 8 ----------------------
SIST EN 50128:2011/A2:2020
EN 50128:2011/A2:2020 (E)
7 Modifications to Clause 5, Software management and organization
In 5.1.2.10 bullet n) replace as follows:

n) A person who is Validator may also perform the role of Verifier, but still maintaining independence from

the Project Manager. In this case, as for all other development activities, the Validator/Verifier outputs

shall be reviewed by another competent person.
In 5.1.2.11 bullet m) replace as follows:

m) A person who is Validator may also perform the role of Verifier, Integrator and Tester. In this case, as for

all other development activities, the Validator/Verifier outputs shall be reviewed by another competent

person.
8 Modifications to 6.2, Software verification
In 6.2.3, Output documents, Bullet 3) is replaced by:
3) Software Planning Verification Report
In 6.2.4, Requirements, 6.2.4.10 is replaced by:

6.2.4.10 A Software Planning Verification Report shall be written, under the responsibility of the Verifier,

on the basis of the input documents from 6.2.2. The Software Planning Verification Report shall be reviewed

by the Validator.
The requirement in 6.2.4.11 refers to the Software Planning Verification Report.
6.2.4.11 is replaced by:

6.2.4.11 Once the software plans have been established (Software Quality Assurance Plan, Software

Configuration Management Plan, Software Verification Plan, Software Validation Plan, and Software

Maintenance Plan) verification shall confirm

a) that the software plans meet the general requirements for readability and traceability in 5.3.2.7 to

5.3.2.10 and in 6.5.4.14 to 6.5.4.17 as well as the specific requirements in 6.2.4.3 to 6.2.4.9,

b) the internal consistency of the software plans,
c) the coherency of the software plans.
The results shall be recorded in a Software Planning Verification Report.
9 Modifications to 6.3, Software validation
In 6.3.3, Output documents:
Remove 3) Software Validation Verification Report
Remove 6.3.4.12, 6.3.4.13 and 6.3.4.14
10 Modifications to 6.4, Software assessment
In 6.4.3, Output documents:
Remove 3) Software Assessment Verification Report
...

SLOVENSKI STANDARD
SIST EN 50128:2011/oprAA:2019
01-junij-2019
Železniške naprave - Komunikacijski, signalni in procesni sistemi - Programska
oprema za železniške krmilne in zaščitne sisteme

Railway applications - Communication, signalling and processing systems - Software for

railway control and protection systems
Bahnanwendungen - Telekommunikationstechnik, Signaltechnik und
Datenverarbeitungssysteme - Software für Eisenbahnsteuerungs- und
Überwachungssysteme

Applications ferroviaires - Systèmes de signalisation, de télécommunication et de

traitement - Logiciels pour systèmes de commande et de protection ferroviaire
Ta slovenski standard je istoveten z: EN 50128:2011/prAA:2019
ICS:
35.240.60 Uporabniške rešitve IT v IT applications in transport
prometu
45.020 Železniška tehnika na Railway engineering in
splošno general
SIST EN 50128:2011/oprAA:2019 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST EN 50128:2011/oprAA:2019
---------------------- Page: 2 ----------------------
SIST EN 50128:2011/oprAA:2019
EUROPEAN STANDARD DRAFT
EN 50128:2011
NORME EUROPÉENNE
EUROPÄISCHE NORM
prAA
March 2019
ICS 35.240.60; 45.020; 93.100
English Version
Railway applications - Communication, signalling and processing
systems - Software for railway control and protection systems

Applications ferroviaires - Systèmes de signalisation, de Bahnanwendungen - Telekommunikationstechnik,

télécommunication et de traitement - Logiciels pour Signaltechnik und Datenverarbeitungssysteme - Software

systèmes de commande et de protection ferroviaire für Eisenbahnsteuerungs- und Überwachungssysteme

This draft amendment prAA, if approved, will modify the European Standard EN 50128:2011; it is submitted to CENELEC members for

enquiry.
Deadline for CENELEC: 2019-06-21.
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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,

Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden,

Switzerland, Turkey 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

© 2019 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.

Project: 68080 Ref. No. EN 50128:2011/prAA:2019 E
---------------------- Page: 3 ----------------------
SIST EN 50128:2011/oprAA:2019
EN 50128:2011/prAA:2019 (E)
Content

European foreword ........................................................................................................................................... 3

1 General Changes....................................................................................................................................... 4

2 Modification to the Introduction .............................................................................................................. 4

3 Modification to the Scope ........................................................................................................................ 4

4 Modification to Clause 2, Normative references .................................................................................... 4

5 Modifications to 3.1, Terms and definitions ........................................................................................... 4

6 Modifications to Clause 4, Objectives, conformance and software safety integrity levels .............. 6

7 Modifications to Clause 5, Software management and organization .................................................. 6

8 Modifications to 6.2, Software verification ............................................................................................. 7

9 Modifications to 6.3, Software validation ............................................................................................... 7

10 Modifications to 6.4, Software assessment ........................................................................................... 7

11 Modifications to 6.5, Software quality assurance .................................................................................. 7

12 Modifications to 6.7, Support tools and languages............................................................................... 8

13 Modifications to Clause 7, Generic software development .................................................................. 9

14 Modifications to Clause 8, Development of application data or algorithms: systems

configured by application data or algorithms ........................................................................................ 9

15 Modifications to Clause 9, Software deployment and maintenance ................................................. 10

16 Modifications to Annex A, Criteria for the Selection of Techniques and Measures ........................ 10

17 Modifications to Annex C ....................................................................................................................... 13

---------------------- Page: 4 ----------------------
SIST EN 50128:2011/oprAA:2019
EN 50128:2011/prAA:2019 (E)
European foreword

This document (EN 50128:2011/prAA:2019) has been prepared by SC 9XA, “Communication, signaling and

processing systems”, of Technical Committee CENELEC TC 9X, “Electrical and electronic applications for

railways”.
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)

The EN 50128:2011 standard was amended to align with EN 50126-1:2017, EN 50126-2:2017 and

EN 50129:2018. In addition, some technical mistakes were corrected and some clarifications were added.

This European Standard should be read in conjunction with EN 50126-1:2017 “Railway applications –

The specification and demonstration of Reliability, Availability, Maintainability and Safety (RAMS) – Part 1:

Generic RAMS Process”, EN 50126-2:2017 “Railway applications – The specification and demonstration of

Reliability, Availability, Maintainability and Safety (RAMS) – Part 2: Systems Approach to Safety” and

EN 50129:2018 “Railway applications – Communication, signalling and processing systems – Safety related

electronic systems for signalling”.
---------------------- Page: 5 ----------------------
SIST EN 50128:2011/oprAA:2019
EN 50128:2011/prAA:2019 (E)
1 General Changes

All occurrences of SIL 0 within EN 50128:2011 are replaced by with Basic integrity (EN 50126-1:2017, 3.7).

All occurrences of safety function(s) are replaced by safety-related function(s).

Use of the term “EN 50126-1” is replaced by “EN 50126-1 and EN 50129-2”.

The term “assessment” in the standard is meant as “independent safety assessment” as per definition of

EN 50126-1:2017, 3.33.

All statements qualified by the words “software safety integrity level” are applicable also to Basic Integrity.

2 Modification to the Introduction
The following paragraph is added at the end of the Introduction:

This European Standard does not specify the requirements for the development, implementation,

maintenance and/or operation of security policies or security services needed to meet security requirements

that may be needed by the safety-related system. IT security can affect not only the operation but also the

functional safety of a system. For IT security, appropriate IT security standards should be applied.

NOTE IEC/ISO standards that address IT security in depth are ISO 27000 series, ISO/IEC TR 19791 and the

IEC 62443 series.
3 Modification to the Scope
The following subclause 1.10 is added:

1.10 For the development of User Programmable Integrated Circuits (e.g. FPGA and CPLD) guidance is

provided in EN 50129:2018, Annex F.
4 Modification to Clause 2, Normative references
Replace the list of normative references by the following:

EN 50126-1:2017, Railway applications – The specification and demonstration of Reliability, Availability,

Maintainability and Safety (RAMS): Generic RAMS Process

EN 50126-2:2017, Railway applications – The specification and demonstration of Reliability, Availability,

Maintainability and Safety (RAMS): Systems Approach to Safety

EN 50129:2018, Railway applications – Communication, signalling and processing systems – Safety related

electronic systems for signalling
EN ISO 9000, Quality management systems – Fundamentals and vocabulary
EN ISO 9001, Quality management systems – Requirements

ISO/IEC 90003, Software engineering – Guidelines for the application of ISO 9001 to computer software

ISO/IEC 9126 series, Software engineering – Product quality
5 Modifications to 3.1, Terms and definitions
Replace 3.1.9 (deleted) with:
3.1.51
error, < in software >

defect, mistake or inaccuracy in the development process which could result in a deviation from the intended

performance or behaviour of the software

Note 1 to entry: definition is derived from EN 50126-1, 3.20 and adapted for software

---------------------- Page: 6 ----------------------
SIST EN 50128:2011/oprAA:2019
EN 50128:2011/prAA:2019 (E)
3.1.52
fault
abnormal condition that could lead to an error in a system
Note 1 to entry: A fault for software is systematic

[SOURCE: IEC 60050-821:2017, 821-11-20, modified – The note 1 to entry has been modified.]

Replace 3.1.10 with:
3.1.10
failure, < of an item >
loss of ability to perform as required

Note 1 to entry: “Failure” is an event, as distinguished from “fault”, which is a state.

[SOURCE: IEC 60050-821:2017, 821-11-19, modified – The notes 1 and 2 have been omitted. A new note 1

to entry has been added.]
Replace 3.1.17 with:
3.1.17
pre-existing software

all software developed prior to the application currently in question is classed as pre-existing software

Note 1 to entry: That includes commercial off-the-shelf software, open-source software and software previously

developed but not in accordance with this European Standard.

[SOURCE: EN 50126-1:2017, 3.43, modified – The end of the definition has been moved to the note 1 to

entry.]
Definition 3.1.26 replaced by:
3.1.26
risk, < for railway RAMS >

combination of expected frequency of loss and the expected degree of severity of that loss

[SOURCE: EN 50126-1:2017, 3.57]
Definition 3.1.27 replaced by:
3.1.27
safety
freedom from unacceptable risk
[SOURCE: IEC 60050-903:2013, 903-01-19]
Definition 3.1.28 replaced by:
3.1.28
safety authority

body responsible for delivering the authorization for the operation of the safety-related system

[SOURCE: IEC 60050-821:2017, 821-12-52]
Remove the term 3.1.29 and its definition (see also General Changes).
Definition 3.1.30 replaced by:
3.1.30
safety-related software
software which performs safety-related functions

Note 1 to entry: software is called safety-related if at least one of its properties is used in the safety argument for the

system in which it is applied. These properties can be of functional or non-functional nature.

[SOURCE: IEC 60050-821:2017, 821-12-60, modified – “safety functions” has been replaced with “safety-

related functions”. The note 1 to entry has been added.]
Definition 3.1.46 replaced by:
---------------------- Page: 7 ----------------------
SIST EN 50128:2011/oprAA:2019
EN 50128:2011/prAA:2019 (E)
3.1.46
validation

confirmation, through the provision of objective evidence, that the requirements for a specific intended use or

application have been fulfilled

Note 1 to entry: The term “validated” is used to designate the corresponding status.

Note 2 to entry: The use conditions for validation can be real or simulated.

Note 3 to entry: In design and development, validation concerns the process of examining an item to determine

conformity with user needs.

Note 4 to entry: Validation is normally performed during the final stage of development, under defined operating

conditions, although it can also be performed in earlier stages.

Note 5 to entry: Multiple validations can be carried out if there are different intended uses.

[SOURCE: IEC 60050-192:2015, 192-01-18]
Definition 3.1.48 replaced by:
3.1.48
verification

confirmation, through the provision of objective evidence, that specified requirements have been fulfilled

Note 1 to entry: The term “verified” is used to designate the corresponding status.

Note 2 to entry: Design verification is the application of tests and appraisals to assess conformity of a design to the

specified requirement.

Note 3 to entry: Verification is conducted at various life cycle phases of development, examining the system and its

constituents to determine conformity to the requirements specified at the beginning of that life cycle phase.

[SOURCE: IEC 60050-192:2015, 192-01-17, modified – The note 3 to entry has been modified.]

Add the following 3.1.50 (in line with EN50126-1):
3.1.50
safety-related
carries responsibility for safety
[SOURCE: IEC 60050-821:2017, 821-01-73]

6 Modifications to Clause 4, Objectives, conformance and software safety integrity

levels
4.4 is replaced by:

4.4 At least the basic integrity requirements of this European Standard shall be fulfilled for the software part

of functions that have a safety impact below SIL 1.

NOTE Basic integrity requirements can also be used for development of non safety-related software.

7 Modifications to Clause 5, Software management and organization
In 5.1.2.10 bullet n) replace as follows:

n) A person who is Validator may also perform the role of Verifier, but still maintaining independence from

the Project Manager. In this case, as for all other development activities, the Validator/Verifier outputs

shall be reviewed by another competent person.
---------------------- Page: 8 ----------------------
SIST EN 50128:2011/oprAA:2019
EN 50128:2011/prAA:2019 (E)
In 5.1.2.11 bullet m) replace as follows:

m) A person who is Validator may also perform the role of Verifier, Integrator and Tester. In this case, as for

all other development activities, the Validator/Verifier outputs shall be reviewed by another competent

person.
8 Modifications to 6.2, Software verification
In 6.2.3, Output documents, Bullet 3) is replaced by:
3) Software Planning Verification Report
In 6.2.4, Requirements, 6.2.4.10 is replaced by:

6.2.4.10 A Software Planning Verification Report shall be written, under the responsibility of the Verifier,

on the basis of the input documents from 6.2.2. The Software Planning Verification Report shall be reviewed

by the Validator.
The requir
...

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