# FRMCS explained

Canonical: https://frmcs.org/knowledge/frmcs-explained
Last reviewed: 2026-10-02
Status: editorial reference page (static legacy content, no stored approval record)

## Short answer

FRMCS (Future Railway Mobile Communication System) is the planned successor to GSM-R for operational railway radio communication. It builds on 3GPP mobile technologies and is specified through the cooperation of railway and telecom standards organisations.

> Brief overview. For the comprehensive guide for decision-makers and engineers, read [What is FRMCS?](/knowledge/was-ist-frmcs-en).

## Why a successor to GSM-R

GSM-R is based on 2G GSM technology. The railway sector initiated FRMCS to move operational communication onto a technology base with a longer support horizon and greater capacity for data-centric applications [1].

## Who is involved

- **UIC** coordinates the railway user requirements and the FRMCS programme from the railway perspective [1].
- **ETSI TC RT** works on the railway-specific system specifications [2].
- **3GPP** standardises the underlying mobile communication features, including mission-critical services [3].
- **ERA** handles the European regulatory side through the interoperability framework [4].

## What this page does not claim

Specific release numbers, dates and deployment timelines change over time. Check the Standards page for versioned, source-linked entries rather than relying on summary text.

## Sources

1. [FU-7100 – FRMCS User Requirements Specification](https://img1.uic.org/IMG/pdf/fu-7100-5.0_0.pdf) — UIC, 5.0.0 (19 Feb 2020)
2. [ETSI TS 103 764 — System Architecture](https://www.etsi.org/deliver/etsi_ts/103700_103799/103764/01.01.01_60/ts_103764v010101p.pdf) — ETSI TC RT, v1.1.1
3. [3GPP TS 22.289 – Mobile communication system for railways (ETSI TS 122 289)](https://www.etsi.org/deliver/etsi_ts/122200_122299/122289/19.00.01_60/ts_122289v190001p.pdf) — 3GPP / ETSI, V19.0.1
4. [CCS TSI Appendix A – mandatory specifications (ETCS B4 R1, GSM-R B1 MR1, FRMCS B0)](https://www.era.europa.eu/era-folder/1-ccs-tsi-appendix-mandatory-specifications-etcs-b4-r1-rmr-gsm-r-b1-mr1-frmcs-b0-ato-b1) — ERA

## Cite as

FRMCS explained. FRMCS Atlas. https://frmcs.org/knowledge/frmcs-explained (last material update 2026-10-02)

> FRMCS Atlas is a personal editorial project by Ante Samardzic (employed by Frequentis), not an official Frequentis, UIC, ETSI or ERA publication or endorsement. Claims are source-linked; review status is stated per page — database articles pass a stored quality review and human approval of the exact version, legacy static pages are marked as such.