Railway Applications — Safety related electronic systems for signalling

Scope

Specifies the requirements for the specification, design, construction and acceptance of safety-related electronic systems (hardware and system aspects) in railway signalling, including safety integrity levels, hardware failure management and the structure of the safety case for generic products, generic applications and specific applications. Together with EN 50126 (RAMS) and EN 50716 (software, successor to EN 50128/50657), it forms the core CENELEC railway safety standard set used by signalling suppliers, infrastructure managers and independent safety assessors.

EN 50129 specifies the requirements for the specification, design, construction and acceptance of safety-related electronic systems used in railway signalling, addressing both hardware and overall system aspects including safety integrity levels, hardware failure-rate management, and the structured safety case documentation required to justify acceptance of a system. It distinguishes between three levels of product genericity -- generic products, generic applications and specific applications -- each requiring a correspondingly scoped safety case, allowing a signalling supplier to reuse safety evidence for a generic product platform across multiple specific deployments. Together with EN 50126 (the overarching RAMS lifecycle framework) and EN 50716 (the software standard that succeeded EN 50128 and EN 50657), it forms the core CENELEC railway signalling safety standard set that signalling suppliers, infrastructure managers and independent safety assessors rely on when developing and accepting new signalling systems. The 2026 edition supersedes the previous BS EN 50129:2018 edition, which will be withdrawn in 2029, giving the sector a multi-year transition period between editions. Its international counterpart is IEC 62425.