The UIC FRMCS Specifications activity is carried out through six working groups, governed by a steering committee and ultimately overseen by ERIG – the UIC Heads of Telecom forum. This work complements UIC’s active participation in 3rd Generation Partnership Project (3GPP) meetings representing the railway sector, as well as its strong support for European Telecommunications Standards Institute (ETSI) Technical Committee on Rail Telecommunications (RT) activities, including holding the chairship.
One of these six bodies is the Architecture & Technology Working Group (ATWG), which is responsible for developing and delivering the Future Railway Mobile Communication System (FRMCS) System Requirements Specification (SRS), and works closely with UNITEL, 3GPP, ETSI RT, and FP2-MORANE2, while also ensuring close coordination with the other UIC FRMCS working groups.
The FRMCS V3 Specifications, which will define the first edition of FRMCS and enable the launch of national pilots, are currently at a critical stage of delivery. The SRS is critical to this deployment, as it translates functional requirements into core system and architecture capabilities.
The first UIC FRMCS ATWG meeting took place in March 2015. More than a decade later, on 27-28 May 2026, the ATWG successfully held its 100th meeting, jointly organised with the Swiss Federal Railways (SBB) in Bern. Over this period, the FRMCS System Requirements Specification has reached a high level of maturity and quality. This complex work requires highly specialised expertise, combining functional requirements with 3GPP radio and mission-critical specifications, as well as advanced connectivity and architectural capabilities.
The 100th ATWG meeting focused on ongoing SRS development and bringing it into closer alignment with the FRMCS Functional Specifications, in preparation for the next version of the specification, scheduled for delivery at the end of November 2026.
Jean-Michel Evanghelou, UIC Director Digital Systems & Innovation, joined the meeting remotely to express UIC’s appreciation for the sustained, high-quality work delivered over the years. He also reaffirmed UIC’s support for the next key challenge: delivering a complete SRS on time to enable the inclusion of FRMCS Version 3 in the 2028 Technical Specification for Interoperability Control Command and Signalling (TSI CCS), which will mark the formal starting point for FRMCS deployment.
UIC remains confident that, despite the challenges ahead, the milestone of delivering the UIC V3 specifications by the end of next year will be achieved.
This achievement will pave the way for the introduction of FRMCS—a 3GPP 5G Standalone Mission-Critical System. FRMCS will go far beyond simply replacing GSM-R; it will provide the foundation for large-scale railway digitalisation, significantly enhancing performance while maintaining and exceeding current safety levels.
