Rail Communications Antennas: GSM-R, TETRA and the Future of Trackside Connectivity

Railway communications infrastructure presents a set of requirements unlike any other sector. Antenna systems must perform reliably at line speed — serving trains travelling at up to 200 mph on high-speed lines — in all weather conditions, through cuttings, tunnels and urban environments, with safety-critical reliability. As the technology underpinning UK rail communications undergoes its most significant change in decades, antenna specification decisions made now will shape infrastructure for the next twenty years.

GSM-R: The Current Standard and Its Sunset

GSM-R (Global System for Mobile Communications – Railway) operates in the 876–915 MHz and 921–960 MHz bands and has been the backbone of UK and European railway communications since the 1990s. It supports train dispatch communications, automatic train protection data links and European Train Control System (ETCS) signalling. The GSM-R standard is now technically obsolete — it runs on 2G technology — and the global harmonised sunset date is set for 2030. Network Rail is already in planning for the successor technology deployment.

FRMCS: The Future Railway Mobile Communication System

FRMCS (Future Railway Mobile Communication System) is the 5G-based successor to GSM-R, standardised by the International Union of Railways (UIC) and the 3GPP standards body. FRMCS uses 5G NR (New Radio) technology in dedicated spectrum — the 900 MHz band re-farmed from GSM-R — and will support not only voice and ETCS data but high-bandwidth applications including CCTV, driver advisory systems and future autonomous train control. For antenna specifiers, FRMCS will require 5G-capable antennas in the 900 MHz and potentially higher frequency bands, with the design rigour that trackside safety-critical equipment demands.

TETRA in Rail

TETRA is widely deployed by rail operators for operational communications independent of the GSM-R signalling network. Station operations, maintenance teams, security and control room communications all use TETRA in many UK rail environments. Unlike GSM-R, TETRA is not facing an immediate sunset — it continues to be the mission-critical voice standard for rail operations, aligned with its continued use in emergency services and other critical infrastructure sectors.

Trackside and On-Board Antenna Considerations

Trackside antenna installations for railway communications must meet the strict mechanical and environmental specifications of the rail environment: vibration resistance, IP66 or higher weatherproofing, compliance with Network Rail and ORR requirements, and mounting systems compatible with trackside furniture. On-board train antennas face additional challenges: aerodynamic profile constraints, vibration from rail joints and switches, and the need to maintain connectivity through tunnels and cuttings where signal levels are inherently lower.

Contact Renair to discuss railway communications antenna requirements: renair.co.uk/contact-us.

Frequently Asked Questions

When will GSM-R be switched off in the UK?

The internationally harmonised GSM-R end-of-life is 2030. Network Rail's specific UK timeline for FRMCS deployment is still in development, with the expectation that critical route migration will occur in the late 2020s. Organisations specifying new trackside infrastructure should plan for FRMCS compatibility.

Can existing GSM-R antennas be used for FRMCS?

Potentially, for antennas covering the 900 MHz band that FRMCS is expected to use. However, FRMCS uses 5G NR with wider channel bandwidths than GSM-R, and antenna performance must be re-verified for the specific FRMCS channel plan before re-use is confirmed.

What IP rating is required for trackside rail antennas?

Trackside antennas are typically specified to IP65 or IP66 as a minimum, protecting against water jet ingress. For below-ground or drainage-adjacent installations, IP67 or IP68 may be required. Network Rail's technical specifications should be the primary reference for any trackside installation.