Ericsson, Swiss National Rail Operator Deliver Europe’s First Live IMS/VoLTE Railway Integration

Wedoany.com Report-Dec.8, Ericsson and Swiss national railway operator SBB have successfully completed Europe's first live integration of the legacy GSM-R railway communications system with a modern IP Multimedia Subsystem (IMS) platform supporting Voice over LTE (VoLTE). The nationwide rollout, completed ahead of schedule in April 2025 and fully operational by December 2025, secures uninterrupted critical communications across Switzerland's 3,100 km rail network following the planned shutdown of public 3G services at the end of 2025.

The upgrade also includes 4G connectivity enhancements for approximately 1,000 trains and 450 operational devices, with zero service interruption recorded during the transition.

Previously, Swiss rail voice services relied on Swisscom's public 3G network in areas without GSM-R coverage. To eliminate this dependency, SBB partnered with Ericsson to implement a future-ready IMS/VoLTE core that seamlessly bridges existing GSM-R functionality with modern mobile and fixed telephony systems while preserving all safety-critical features, including emergency stop calls, functional numbering, group calls and onboard announcements.

Key project milestones:
- June 2023: IMS platform deployment began
- Early 2024: First successful end-to-end VoLTE-to-GSM-R calls
- January 2025: Extensive field testing on pilot trains, certified by Switzerland’s Federal Office of Transport
- April 2025: Nationwide go-live achieved ahead of target
- December 2025: Full operational status with ongoing migration of remaining fleet devices

The converged solution integrates equipment from multiple vendors and provides scalable, high-performance dispatcher telephony while creating a clear technical path toward the future 5G-based Future Railway Mobile Communication System (FRMCS).

Nicolas Segond, Head of Mission Critical Communications for Railways in Europe, Middle East and Africa at Ericsson, said: "Our work with SBB demonstrates our capability to deliver complex digital transformations under tight timelines. We look forward to setting benchmarks in railway communication innovation and supporting the transition to FRMCS in the coming years."

The successful project positions Switzerland's railway system as a European reference for managing the transition away from legacy 2G/3G technologies while maintaining the highest standards of safety and reliability.