UNE-EN 50128-2012 A1-2020 PDF

Full title and description

STB UNE-EN 50128:2012/A1:2020 — Railway applications: Communication, signalling and processing systems — Software for railway control and protection systems. This item is the A1 amendment to the UNE-EN 50128:2012 national adoption of the CENELEC EN 50128 software safety standard, clarifying and updating requirements for software lifecycle, verification and the handling of pre-existing or generic software used in safety-related railway systems.

Abstract

This amendment (A1:2020) provides targeted changes and clarifications to the UNE-EN 50128:2012 text for software used in railway control and protection systems. It emphasises lifecycle processes, verification/validation evidence, treatment of pre-existing and generic software, tool qualification and the relationship between software assurance and applicable interoperability/safety directives. The amendment is a short normative change to the base standard and is intended to be used alongside the full UNE-EN 50128:2012 text.

General information

• Status: Superseded / amended — this A1 amendment was published as a national adoption; the UNE/EN family has later been consolidated by newer software standards (see Related standards).
• Publication date: 07 October 2020 (UNE edition / national publication).
• Publisher: Asociación Española de Normalización (AENOR) as UNE national adoption of the CENELEC EN 50128 amendment; original EN text published under CENELEC.
• ICS / categories: 35.240.60 (IT applications in transport); 45.020 (Railway engineering in general); 93.100 (Construction of railways).
• Edition / version: UNE-EN 50128:2012 / Amendment A1:2020 (designation: UNE-EN 50128:2012/A1:2020).
• Number of pages: Amendment document: approx. 5–6 pages (A1 amendment only). For the full base standard see UNE-EN 50128:2012 (main document ~149 pages).

Scope

Applies to all safety-related software used in railway control and protection systems, including application code, operating systems, firmware, support tools and generic software components (including configurable items). The amendment clarifies requirements on lifecycle processes, verification and validation, use and assessment of pre‑existing software, tool qualification, and responsibilities for demonstrating conformity with safety objectives and applicable interoperability directives. It complements the full UNE-EN 50128:2012 clauses and is intended primarily for new developments and major modifications.

Key topics and requirements

• Software safety lifecycle: definition and tailoring of phases (requirements, design, implementation, verification, validation and maintenance) consistent with assigned Safety Integrity Levels (SILs).
• Verification and validation: evidence requirements, testing strategies, coverage targets and independence of verification activities.
• Treatment of pre-existing and generic software: rules for re-use, evidence expected for previously developed software, and handling of configurable generic components.
• Tool qualification: criteria and evidence for development/verification tools that can impact software safety.
• Configuration management and documentation: required artefacts, traceability from requirements to tests and maintenance records.
• Responsibilities and assessment: clarity on manufacturer/supplier obligations and expectations for assessors and certification bodies.
• Regulatory alignment: references and mapping to EU interoperability/safety requirements (Annex ZZ style relationship to directives and TSIs where applicable).

Typical use and users

This amendment and the underlying UNE-EN 50128:2012 standard are used by software engineers, system integrators, safety and assurance engineers, project managers, procurement teams, test laboratories, independent assessors and certification authorities involved in railway signalling, control and protection projects. It is referenced in contractual specifications, safety cases, procurement documentation and conformity assessment activities.

Related standards

Commonly used together with: UNE-EN 50126 (RAMS and lifecycle processes), UNE-EN 50129 (safety-related electronic systems for signalling), UNE-EN 50159 (safety-related communication), UNE-EN 50657 (software for rolling stock) and more recent consolidated documents such as UNE-EN 50716:2023 which updates and harmonises railway software requirements.

Keywords

railway software, EN 50128, software safety, SIL, verification, validation, signalling, control systems, pre-existing software, tool qualification, lifecycle, A1 amendment, UNE-EN.

FAQ

Q: What is this standard?

A: It is the A1 amendment (2020) to the UNE-EN 50128:2012 national adoption of the CENELEC EN 50128 standard, which sets processes and technical requirements for software used in railway control and protection systems.

Q: What does it cover?

A: The amendment clarifies and updates elements of the software lifecycle, verification/validation evidence, use and assessment of pre-existing or generic software, tool qualification and the documentation and responsibilities needed to demonstrate compliance for safety‑related railway software. It does not replace the full standard text but modifies specific clauses.

Q: Who typically uses it?

A: Software developers, system integrators, safety engineers, test laboratories, independent assessors, certification bodies, project managers and procurers in the railway signalling and control domain.

Q: Is it current or superseded?

A: The A1:2020 amendment was published in 2020 (UNE national edition 07 October 2020). Subsequent consolidation and newer CENELEC/UNE documents for railway software (for example UNE-EN 50716:2023) have since been published and may supersede or consolidate earlier texts; check the current national catalogue for the definitive active reference before use.

Q: Is it part of a series?

A: Yes — it is part of the EN 5012x family addressing railway safety and software: EN 50126 (system lifecycle / RAMS), EN 50128 (software), EN 50129 (signalling electronic systems) and related documents (EN 50159, EN 50657, etc.). Amendments A1/A2 and national adoptions (UNE-EN, NF-EN, SS-EN, etc.) are common.

Q: What are the key keywords?

A: Railway software, safety integrity level (SIL), verification & validation, pre-existing software, tool qualification, signalling, control and protection systems, software lifecycle, UNE-EN 50128, A1:2020.