Railway Applications — Safety-related communication in transmission systems

Scope

Specifies requirements for safe data communication between safety-related railway signalling and processing equipment over both closed and open transmission networks, defining the communication threats (repetition, deletion, insertion, resequencing, corruption, delay, masquerade) and the defences required against each. Part of the CENELEC railway safety family alongside EN 50126, EN 50128 and EN 50129, it is applied by signalling suppliers and independent safety assessors for systems such as ETCS data transmission and interlocking communication.

EN 50159 specifies requirements for safe data communication between safety-related railway signalling and processing equipment, applicable both to closed transmission networks under a single authority's control and to open networks where the transmission medium cannot be assumed trustworthy. It identifies a defined set of communication threats -- repetition, deletion, insertion, resequencing, corruption, delay and masquerade of messages -- and specifies the technical defences, such as sequence numbers, time stamps, identifiers and cryptographic techniques, required to protect against each threat according to the safety integrity level of the application. As part of the CENELEC railway safety family alongside EN 50126, EN 50129 and the software standards, it is applied by signalling suppliers and independent safety assessors when designing and assessing communication-dependent systems such as ETCS radio data transmission and interlocking-to-interlocking or interlocking-to-object-controller communication links. The standard is currently under revision, with a successor edition, EN 50159:2026, scheduled for publication, while the 2010+A1:2020 edition remains the applicable reference in the meantime.