Pioneering the next era of railway communications

From standards completion to FRMCS readiness

Railways worldwide are reaching a critical point in their digital transformation. Increasing traffic volumes, growing cross-border operations, and rising expectations for safety, efficiency, and passenger experience are placing new demands on communications infrastructure. While GSM-R has served the industry reliably for decades, future rail operations require richer data, real-time situational awareness, and seamless interoperability across networks and generations of technology.

This is the role of the Future Railway Mobile Communication System (FRMCS). Designed as the successor to GSM-R, FRMCS provides a standardized, 5G-based foundation for mission-critical railway communications, while enabling new operational and passenger-facing services.

At Nokia, we have been working closely with the global rail ecosystem to help advance this transition. Recent milestones—including the launch of commercial 5G railway solutions and the world’s first 1900 MHz 5G FRMCS radio deployment on Deutsche Bahn’s test track—demonstrate that FRMCS is moving beyond concept and trials toward deployable infrastructure.

A major step in this journey is the completion of Stage 3 normative work for 3GPP Release 19 FRMCS_Ph5. With this final stage concluded, the industry now has a complete and fully standardized technical foundation for the first wave of FRMCS rollouts.

Laying tracks for seamless mission-critical services

From Release 15 to Release 19

FRMCS has evolved progressively across successive 3GPP releases, each adding essential capabilities for railway operations.

Release 15 introduced functional addressing and multi-talker group call features, enabling communications to be organized by role rather than by individual device. This significantly improved coordination across operational teams.

Release 16 strengthened mission-critical reliability through unified priority handling and pre-emption, alongside multi-device support for mission-critical push-to-talk (MCPTT). These capabilities ensure assured delivery of critical communications, even during network congestion or disruption, while providing greater flexibility for field personnel.

Release 17 brought robust mission-critical services into the 5G domain. Lower latency, improved bandwidth management, and support for gateway user equipment and IP connectivity simplified the interworking of legacy railway infrastructure with modern 5G systems.

Release 18 focused on migration and interoperability. Enhancements to group and broadcast communications, improved emergency handling, and real-time location tracking for staff and trains support safer and more efficient operations. Seamless interworking capabilities enable phased migration and cross-border railway operations.

Release 19 completes this evolution. Advanced gateway capabilities, more responsive ad-hoc group communications, and unified location protocols help operators coordinate teams more effectively across diverse networks and national environments. With Release 19 specifications finalized, rail operators can adopt a mature, fully standardized FRMCS feature set with confidence.

Translating standards into operational FRMCS networks

Standards maturity is only meaningful when it translates into deployable systems. FRMCS is a system-of-systems, requiring close integration across radio, transport, core, service, management, and security layers.

At the radio layer, FRMCS depends on ultra-reliable, low-latency connectivity between trains, trackside infrastructure, and operational centers. Nokia’s n101 (1900 MHz) and upcoming n100 (900 MHz) radios are designed for high-speed, safety-critical railway environments, combining modular architecture, cloud-native flexibility, and AI-driven energy awareness.

Beyond connectivity, FRMCS enables a new generation of services. Operational applications—including signaling support, maintenance, and monitoring—can be integrated with passenger services to create more efficient workflows and improved travel experiences, helping operators reduce downtime while enhancing service quality.

Reliable transport networks connect the RAN, core, and service layers. Multi-service IP/MPLS and optical transport solutions are engineered for railway topologies, delivering high capacity, low latency, synchronization, traffic isolation, and zero-trust security. Optical WDM supports RAN fronthaul requirements, while IP/MPLS and segment routing address 5G backhaul needs across the wide-area network.

Effective management and automation are essential to operating FRMCS at scale. End-to-end visibility enables self-optimization, predictive maintenance, and intelligent energy management, allowing operators to dynamically balance performance, availability, and power consumption.

Security and compliance are fundamental, as railways represent critical national infrastructure. Protections are embedded across the architecture, aligned with 3GPP, UIC, and national regulatory frameworks, safeguarding the confidentiality, integrity, and availability of communications.

At the core of the architecture, a resilient 5G Core provides high throughput, low latency, and network slicing to separate safety-critical services from passenger applications. Cloud-native deployment on on-premises platforms supports continuity with GSM-R during transition while providing a clear path to modernization. Mission-critical services—including push-to-talk, data, and video—complete the FRMCS framework, ensuring secure and reliable coordination even under heavy load or emergency conditions.

From specification to deployment

With 3GPP Release 19 FRMCS specifications complete, the industry reaches an important inflection point. The focus now shifts from defining standards to deploying operational FRMCS networks.

For railway operators, this provides clarity: standards are mature, migration paths are defined, and interoperability across borders and technologies is supported. FRMCS is ready to move from planning to implementation.

At Nokia, we remain committed to supporting this transition, working with railways and ecosystem partners to turn FRMCS from specification into operational reality as the next era of railway communications takes shape. If you’d like to know more, visit our Nokia Railway Solutions web page.