The 2023 revision of the Technical Specifications for Interoperability was the largest coordinated update since the TSIs were born: one amending regulation swept across the structural TSIs while a full recast rebuilt the control-command and signalling TSI around ETCS Baseline 4. This page maps the package; each linked entry carries the consolidated detail.
The instruments
Three regulations did the work. Implementing Regulation (EU) 2023/1694 amended, in a single act, the TSIs for freight wagons, infrastructure, accessibility, energy, locomotives and passenger rolling stock and noise, together with the RINF regulation — each TSI keeping its founding regulation number, as amended. Regulation (EU) 2023/1695 recast the CCS TSI outright, repealing the 2016 version. A parallel act updated the operation and traffic management TSI. The shared policy drivers: automation, digitalisation and the competitiveness of rail freight.
The CCS recast: the package's centre of gravity
The new CCS TSI is where the 2023 package changes daily engineering life. Its Annex A pins the ERTMS specification set at ETCS Baseline 4 — SUBSET-026 v4.0.0 and companions — brings ATO over ETCS into the mandated set via SUBSET-125/126, and structures the radio layer for the GSM-R to FRMCS migration. A 2026 amendment has since refreshed the testing specifications and transitional measures. If you read one comparison alongside this page, read Baseline 3 vs Baseline 4.
The structural TSIs: targeted, not cosmetic
Across LOC&PAS, WAG, INF, ENE, NOI and PRM the 2023 amendments are surgical updates rather than rewrites: refreshed references to current EN editions (the OJ harmonised-standards list moved in parallel — see each entry's Official Journal references on its page), requirements supporting freight digitalisation and automation, and alignment of the RINF register with the data the amended TSIs need. For practitioners the operative rule is unglamorous but vital: work from the consolidated versions, because every one of these TSIs now reads differently than its founding regulation.
Telematics: the quiet consolidation
The package's aftermath also settled the telematics layer: the separate TAF (freight) and TAP (passenger) telematics TSIs were merged by Implementing Regulation (EU) 2026/253 into a single Telematics TSI with effect from 1 March 2026 — closing a long-signposted duplication.
How to use this in practice
For a running project, three questions locate you on the map. Which consolidated TSI text applies to your subsystem and date? Which EN editions does the current OJ list cite for your presumption of conformity (each library entry shows its cited editions)? And for CCS work, which Annex A versions govern your baseline? The application guides — general and CCS-specific — remain the best official companions for the mechanics.