On this page
- EN 50126, EN 50128, EN 50716 and EN 50129 compared
- Has EN 50716 replaced EN 50128?
- How RAMS and SIL fit together
- Which references belong in your railway project?
- Buying guides for individual railway references
- Check editions before obtaining the documents
- Railway standards questions
- Related guidance
EN 50126, EN 50128, EN 50716 and EN 50129 compared
Catalogue information checked: 24 September 2026. National publication dates and amendment packaging can differ. These references are a starting point for document selection, not a project approval.
| Reference | Main purpose | Edition and selection check |
|---|---|---|
| EN 50126-1 | The overall process for managing reliability, availability, maintainability and safety (RAMS) throughout a railway system's life. | Check EN 50126-1:2017 with A1:2024. The EVS consolidated record identifies both documents. |
| EN 50126-2 | The system approach to safety, including deriving safety requirements and allocating them to subsystems. | Check EN 50126-2:2017 with A1:2024. See the EVS consolidated record. |
| EN 50716 | Software development for railway signalling and software on rolling stock, including its interaction with the surrounding system. | EN 50716:2023 is the successor to EN 50128 and EN 50657. DIN's adoption record lists the replaced publications and subsequent corrections. |
| EN 50128 | The earlier software standard for railway control and protection, still encountered in existing project specifications and evidence. | Establish the accepted project baseline before changing a legacy reference. Read the EN 50716 scope for existing software and modifications. |
| EN 50129 | Functional safety of electronic systems used for railway signalling, including subsystems and equipment. | EN 50129:2026 has been published. EVS lists the new edition and withdrawal of its 2018 adoption. Check transition arrangements for your project. |
Has EN 50716 replaced EN 50128?
Yes. EN 50716 brings the earlier signalling and rolling-stock software standards into one software-development reference. DIN's replacement list includes its EN 50128 and EN 50657 adoptions and their listed amendments. A national adoption may carry a later publication date: DIN EN 50716:2024-09 implements EN 50716:2023. Check the DIN replacement record.
That replacement does not mean every existing software system must be redeveloped. The published EN 50716 scope distinguishes new development, major modifications and minor changes, and addresses software developed under earlier EN 50128 or EN 50657 editions. Record what is changing, the existing evidence and the agreed assessment approach before updating a project's references. Read the EVS scope summary.
How RAMS and SIL fit together
RAMS covers reliability, availability, maintainability and safety. EN 50126-1 provides the overall lifecycle process; it does not set one universal performance target for every railway application. Its scope includes signalling, rolling stock and fixed installations. Read BSI's Part 1 scope.
A Safety Integrity Level (SIL) should follow the analysis of the safety-related electronic function. EN 50126-2 describes methods for deriving safety requirements and SILs. A product name such as a door controller, display or braking system is not enough to select a SIL from a generic table; define the function, hazards, interfaces and operating assumptions first. Read the Part 2 scope.
Which references belong in your railway project?
Start with a short applicability record. These questions help a supplier, purchaser or assessor establish the document set and avoid mixing editions without an explanation.
- Define the system and boundaries. Identify the equipment, software, interfaces and intended operating environment, together with the part of the railway in which it will be used.
- Identify the governing requirements. Record relevant legislation, Technical Specifications for Interoperability (TSIs), project specifications and acceptance arrangements. Identify the exact standards references they call up.
- Distinguish new work from changes. List new or modified functions and the parts remaining unchanged. Keep existing design and acceptance evidence traceable.
- Record complete references. Include the national designation, part, year, amendments, corrections and language. Distinguish a standalone amendment from a consolidated publication.
- Agree responsibilities and evidence. Identify who owns requirements, hazard analysis, software evidence, system evidence and assessment decisions, and how unresolved issues will be closed.
European standards are generally voluntary, but a standard specified in a mandatory TSI can become mandatory through that reference. Check the actual TSI and project requirements rather than assuming the same three standards apply identically to every project. ERA explains the relationship between EN standards and TSIs.
Buying guides for individual railway references
Move from the family comparison to the document and evidence questions for your project:
- EN 50126-1 RAMS process buying guide — define the lifecycle task and check how the base document and amendment are supplied.
- EN 50126-2 systems safety buying guide — clarify hazards, interfaces, responsibilities and allocated requirements.
- EN 50716 railway software buying guide — distinguish the published document, legacy references and the evidence for new or changed software.
- EN 50129 signalling safety buying guide — compare generic product evidence with the particular installation and project baseline.
Each guide includes supplier questions and verified catalogue links. Agree the relevant project baseline and assessment responsibilities before changing an existing specification.
Check editions before obtaining the documents
Use the external catalogue links to locate the references you need. Confirm the full designation, included amendments, publisher status, language and licence for the people who will use the documents. An older edition named in an existing contract needs an applicability decision; a new catalogue edition alone does not explain how a particular accepted system must change.
Search railway standards in Genorma's external catalogue. Review the selected record's edition, availability, format and price with the provider.
Keep a standards register containing the selected reference, its purpose, source, check date and reason that edition is being used. Recheck it when the design, contract, applicable requirements or publisher record changes.
Railway standards questions
What changed since EN 50126, EN 50128 and EN 50129 became known as a trio?
Check the 2024 amendments to both EN 50126 parts, the EN 50716:2023 software reference, and EN 50129:2026. The comparison links to publisher records; it does not claim every project's accepted baseline changed on the same date.
Is EN 50129 only a hardware standard?
Its scope concerns functional safety of electronic signalling systems, including subsystems and equipment. Treating it only as a hardware checklist overlooks the system-level scope. It does not establish the safety authority's approval process. Read the EN 50129:2026 scope.
Does EN 50129:2026 invalidate an existing accepted system?
No automatic conclusion follows from the publication year alone. The published scope discusses previously accepted systems and modifications, including cases where modified and unchanged parts use different versions. Review the change and applicable acceptance arrangements. Read BSI's 2026 scope.
Does this guide replace the standards or a railway safety assessment?
No. It helps identify references and prepare questions. Use the licensed documents for their requirements and obtain the competent engineering and assessment input appropriate to the project.
Related guidance
- What CENELEC standards cover and how to find them
- Legal access to EN and ISO standards
- Choose a standards licence for your team
Source check: 24 September 2026. This comparison uses public publisher catalogue records and ERA guidance. It does not reproduce the standards or record an independent technical review of a particular railway project.