Railways Applications — Rolling stock applications — Software on board rolling stock

Scope

Specifies process and technical requirements for the development, deployment and maintenance of software for programmable electronic systems on board rolling stock, covering non-signalling onboard functions such as train control and management, HVAC and passenger information systems. Adapted from EN 50128, it defines software integrity levels from basic integrity to SIL 4 and was used by rolling-stock suppliers, RUs and assessors for onboard software assurance. Superseded by EN 50716:2023, which merges EN 50128 and EN 50657 into a single railway software development standard.

EN 50657 specified the process and technical requirements for developing, deploying and maintaining software running on programmable electronic systems installed on board rolling stock, covering non-signalling functions such as train control and management systems, HVAC control and passenger information systems, as distinct from the trackside signalling software addressed by EN 50128. Adapted directly from EN 50128's process framework, it defined software integrity levels ranging from basic integrity up to SIL 4, and was used by rolling-stock suppliers, railway undertakings and independent assessors to assure the safety and quality of on-board software throughout its lifecycle. It has been superseded by EN 50716:2023, which merges EN 50128 (trackside and signalling software) and EN 50657 (on-board software) into a single railway software development standard covering both domains under one common set of requirements. EN 50657 was formally withdrawn on 7 May 2025 following the publication of its successor. Suppliers previously certifying on-board software against EN 50657 have transitioned to demonstrating compliance with EN 50716.