International Standards and Conformity Assessment for all electrical, electronic and related technologies



Reference EN 50128:2011
Title Railway applications - Communication, signalling and processing systems - Software for railway control and protection systems
Project Number 20508
Abstract/Scope 1.1 This European Standard specifies the process and technical requirements for the development of software for programmable electronic systems for use in railway control and protection applications. It is aimed at use in any area where there are safety implications. These systems can be implemented using dedicated microprocessors, programmable logic controllers, multiprocessor distributed systems, larger scale central processor systems or other architectures. 1.2 This European Standard is applicable exclusively to software and the interaction between software and the system of which it is part. 1.3 This European Standard is not relevant for software that has been identified as having no impact on safety, i.e. software of which failures cannot affect any identified safety functions. 1.4 This European Standard applies to all safety related software used in railway control and protection systems, including – application programming, – operating systems, – support tools, – firmware. Application programming comprises high level programming, low level programming and special purpose programming (for example: Programmable logic controller ladder logic). 1.5 This European Standard also addresses the use of pre-existing software and tools. Such software may be used, if the specific requirements in and on pre-existing software and for tools in 6.7 are fulfilled. 1.6 Software developed according to any version of this European Standard will be considered as compliant and not subject to the requirements on pre-existing software. 1.7 This European Standard considers that modern application design often makes use of generic software that is suitable as a basis for various applications. Such generic software is then configured by data, algorithms, or both, for producing the executable software for the application. The general Clauses 1 to 6 and 9 of this European Standard apply to generic software as well as for application data or algorithms. The specific Clause 7 applies only for generic software while Clause 8 provides the specific requirements for application data or algorithms. 1.8 This European Standard is not intended to address commercial issues. These should be addressed as an essential part of any contractual agreement. All the clauses of this European Standard will need careful consideration in any commercial situation. 1.9 This European Standard is not intended to be retrospective. It therefore applies primarily to new developments and only applies in its entirety to existing systems if these are subjected to major modifications. For minor changes, only 9.2 applies. The assessor has to analyse the evidences provided in the software documentation to confirm whether the determination of the nature and scope of software changes is adequate. However, application of this European Standard during upgrades and maintenance of existing software is highly recommended.


Current Stage code 6060
Current Stage code date 2011-06-17
Current Stage code deadline 2012-04-25
Deadline date for vote 2008-12-31


Order Voucher  


IEC Technical Body  
Reference Document  
ICS 35.240.60 - IT applications in transport and trade
45.020 - Railway engineering in general
93.100 - Construction of railways
Keywords Railway application; Communication; Signalling; Protection; Software
Note 2011-03-21 - Publication editing allocated to * Supersedes EN 50128:2001 * Corrigendum published to extend DOW to DOR + 72 months, to read 2017-04-25 (see PR=25340)
Special National Condition(s)  


Categories - Aspects
Product Life Cycle


Deadline Date
6060 2011-06-17 2012-04-25 export to doc file  EN  FR  DE
5099 2011-04-25 2011-05-23  
5060 2011-03-21 2011-04-11 export to doc file  EN
5020 2011-01-14 2011-03-18 export to doc file  EN  FR  DE
4099 2010-04-14 2010-09-30  
4060 2010-01-12 2010-05-12 export to doc file  EN
4020 2009-07-31 2010-01-08 export to doc file  EN
3099 2008-12-04 2009-08-22  
3020 2008-04-01 2008-07-31  
2020 2006-11-07 2008-04-30  
1099 2005-12-06 2006-06-06  

Implementation Dates

date of Ratification (DOR) (1) 2011-04-25
date of Availability (DAV) (2) 2011-06-17
date of Announcement (DOA) (3) 2011-10-25
date of Publication (DOP) (4) 2012-04-25
date of Withdrawal (DOW) (5) 2017-04-25


Supersedes EN 50128:2001
Superseded by  
Normative reference (6)  

(1) Date of ratification (dor) date when the Technical Board notes the approval of an EN (and HD for CENELEC), from which time the standard may be said to be approved

(2) Date of availability (dav) date when the definitive text in the official language versions of an approved CEN/CENELEC publication is distributed by the Central Secretariat

(3) Date of announcement (doa) latest date by which the existence of an EN (and HD for CENELEC), a TS or a CWA has to be announced at national level

(4) Date of publication (dop) latest date by which an EN has to be implemented at national level by publication of an identical national standard or by endorsement

(5) Date of withdrawal (dow) latest date by which national standards conflicting with an EN (and HD for CENELEC) have to be withdrawn

(6) This list of normative references is purely indicative. The only official list of normative reference is the list of the published standard.