EULYNX Baseline Set 4 Release 4 — interlocking interfaces

Scope

Specification set defining a modular interlocking architecture with standardised interfaces between interlockings and trackside field elements (point machines, signals, level crossings), published jointly by EULYNX and the EU-Rail System Pillar. Release 4 finalises Baseline Set 4 with 25 common specification documents plus 24 supporting EULYNX-architecture documents, and is now closed to functional changes. Used by infrastructure managers and signalling suppliers to decouple interlocking and field-element procurement and reduce vendor lock-in.

EULYNX Baseline Set 4 Release 4 is a specification set defining a modular interlocking architecture with standardised interfaces between interlockings and trackside field elements such as point machines, signals and level crossings, published jointly by the EULYNX consortium of European infrastructure managers and the Europe's Rail System Pillar. Release 4 finalises Baseline Set 4 with 25 common specification documents covering the core interfaces, plus 24 supporting documents describing the wider EULYNX architecture, and the baseline is now closed to further functional changes. By standardising the interfaces between interlockings and field elements, the specifications let infrastructure managers procure interlockings and field elements from different suppliers independently of one another, reducing reliance on any single vendor's proprietary, end-to-end signalling system. Infrastructure managers and signalling suppliers use the specification set to design and tender modular signalling renewals and new-build projects based on the EULYNX interface model. The full specification pack is downloadable by registered users of the EULYNX website, and Release 4 (published 26 June 2025) is confirmed as the final, most current release of Baseline Set 4.