Future Railway Mobile Communication System

Future Railway Mobile Communication System (FRMCS) is the future worldwide telecommunication system designed by UIC, in close cooperation with the different stakeholders from the rail sector, as the successor of GSM-R but also as a key enabler for rail transport digitalisation.

Visit FRMCS website:

What is FRMCS, the Future Railway Mobile Communication System?

General context

The European railways currently use the GSM-R system for operational communication, a key component of the European Railway Traffic Management System ERTMS.

Designed 20+ years ago by UIC and completely border-crossing interoperable, GSM-R, which is a 2G+ based system, is deployed on more than 130,000 kilometers of track in Europe (with 90.000 activated On Board Cab Radio’s), and some 210,000 kilometers worldwide.

The Future Radio Mobile Communication System (FRMCS) is the Railways response for two elements of strategic importance for the future of the railways:

First – the fast-coming GSM-R obsolescence, which is European level risk for Railways ERTMS continuity (2035);

Second - it is also a significant opportunity, which is to enable and support the Railways Digitalization, and therefore the need to transmit, receive and use increasing volumes of data, which is at the very heart of sustainable transport.

These considerations led UIC to launch the studies for a successor to GSM-R, pertinently named Future Rail Mobile Communications System (FRMCS), and to put in place ta solid organisation capable to build the FRMCS specifications, and also to monitor and involve directly in the relevant activities related to FRMCS introduction.

The UIC FRMCS activity is governed via below working groups:

  • The FRMCS Steering Group leads the global FRMCS strategy and planning,
  • The FRMCS Functionality Working Group (FWG) ensures the adequate matching between system functionalities and railway needs,
  • The FRMCS Architecture and Technology Group Working Group (ATWG) has the mission to define the FRMCS architectures, and the system requirements,
  • The FRMCS Telecom On-Board Architecture has the mission to define the On-Board FRMCS that uses the acronym (TOBA architecture) and functional requirements.
  • The UIC Group for Frequency Aspects (UGFA) takes care of the expected needs for spectrum, particularly sensitive in the transition scenarios.
  • FRMCS FIS (Functional Interface Specifications), defining the call flows to determine any gaps or inconsistencies,
  • FRMCS FFFIS (Form-Fit-Functional Interface specification), defining the On Board and Track Side Applications interface, responsible with the definition of the FRMCS border interface specifications,

These working groups are interfaced with UNITEL, ERA, and ETSI TC RT.

The missions of these groups also encompass the following key activities:

  • Build and deliver the FRMCS specifications:
  • Obtain dedicated frequencies for FRMCS in Europe

The build and delivery of the FRMCS Specifications follows the European Process, as they are meant to be introduced in CCS TSI.

The FRMCS specifications will be completed with ETSI Technical specifications, delivered by the ETSI Railway Telecom technical committee.

The current FRMCS introduction situation is:
FRMCS Frequencies (additional to GSM-R) have been secured in Europe, see ECC (20) 02.
Version 1 (V1) of the FRMCS Specifications have been finalized following the UIC and ERA Change -Control – management processes.

2023 CCS TSI have included:

  • FRMCS introduced as GSM-R successor.
  • GSM-R and FRMCS are considered together as the railway Mobile Radio System(s) – RMR
  • FRMCS will work in coexistence with GSM-R (until somewhere 2035)
  • The FRMCS specifications are introduced within the TSI Annex A

V1 specifications are included within this page. As already mentioned in the CCS TSI, they are for now not considered for procuring products.
Next steps for the FRMCS introduction have been agreed with DG Move. EU-Rail JU and ERA. The major steps and milestones can be seen below:


Dan Mandoc, Head of FRMCS

Jean-Michel Evanghelou, Director Telecom & Signaling, ERIG Chairman

FRMCS Documents

FRMCS and 5G for rail: challenges, achievements and opportunities

- PDF - 2 Mb

Description and Evaluation of Possible FRMCS MIgration Variants for Existing ETCS and Cab Radio On-Board Units-TOBA 7515-v1.2

- PDF - 1.1 Mb

FRMCS Telecom On-Board System -Architecture Migration Scenarios-TOBA7540-1.0.0

- PDF - 3.1 Mb

FRMCS Use Cases-MG 7900-v2.1.0

- PDF - 3.3 Mb

FRMCS User Requirements Specification Review Sheet Template

- Excel - 53 kb

FRMCS User Requirements Specification-FU 7100-v5.1.0

- PDF - 1.9 Mb


FRMCS Specifications

FRMCS Functional Requirements Specification FU-7120-1.0.0.pdf

- PDF - 3.9 Mb

TOBA Functional Requirements Specification TOBA-7510-1.0.0.pdf

- PDF - 1.8 Mb

FRMCS System Requirements Specification AT-7800-1.0.0.pdf

- PDF - 1.8 Mb

FRMCS FFFIS -7950 1.0.0.pdf

- PDF - 1.1 Mb

FRMCS FIS-7970 1.0.0.pdf

- PDF - 3.2 Mb


Other Regions

The UIC FRMCS Specifications are intended for global use, much like the current UIC GSM-R Specifications. With this in mind, the UIC has been exploring the worldwide application of FRMCS.

However, certain countries may face challenges in accessing the 5G framework and technologies due to factors such as unavailability or high cost of 5G spectrum, national 5G development schedules, and the cost of owning 5G technologies.

These countries might also encounter early migration constraints and time-to-market issues. To address these challenges, a specific Technical Guideline, known as FRMCS-Transition (“FRMCS-T”), was developed.

FRMCS – Transition, Technical Guidelines

- PDF - 683.9 kb

FRMCS и 5G для железнодорожного транспорта проблемы, достижения и перспективы

- PDF - 2.6 Mb

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Tuesday 19 September 2023