# GSM-R to FRMCS migration

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

## Short answer

Migration from GSM-R to FRMCS is expected to include a period of coexistence in which both systems operate in parallel. Planning typically covers onboard fleet equipment, trackside infrastructure, spectrum, operational procedures and cross-border interoperability.

## Planning dimensions

1. **Coexistence** – how long both systems run in parallel and how services are handed over.
2. **Onboard** – retrofit or new-build equipment across mixed fleets.
3. **Trackside** – radio sites, core network and backhaul.
4. **Spectrum** – frequency availability under national and European rules [3].
5. **Operations** – procedures, training and incident handling.

## Interoperability

For cross-border operation in Europe, the interoperability framework (TSI) defines mandatory requirements; check ERA for the version in force [3].

## What we do not state

This page does not give country-specific timelines. Where such dates appear on the Standards page, they are labelled as planned or confirmed and linked to the original source.

## 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. [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

GSM-R to FRMCS migration. FRMCS Atlas. https://frmcs.org/knowledge/gsm-r-to-frmcs-migration (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.