The European Rail Traffic Management System (ERTMS) is the EU’s common standard for train control and railway radio. By the end of 2024, its train control component was in service on about 10% of the trans-European transport network and fitted to 19% of the EU fleet.
The figures come from the third work plan of the European Commission’s ERTMS coordinator, Matthias Ruete, published in February 2026: 12,400 km of track and 8,730 vehicles. EU law requires the core network to be equipped by the end of 2030.
ERTMS is designed to replace the national signalling systems that make borders hard to cross. Every line and every train has to be converted, and the two sides have to match.
What ERTMS replaces
Each European country developed its own train protection system. EU law groups these national systems as class B. A train needs onboard equipment for every class B system on its route, and a driver trained to use each one. The high-speed trains between Paris and Cologne carry six different train control systems, according to Danish infrastructure manager Banedanmark.
The national systems are one reason European trains struggle to run across borders. ERTMS replaces them with a single specification in two parts: the European Train Control System (ETCS), which supervises the train, and a dedicated railway radio network that links train and ground.
The rules sit in the EU’s technical specification for control-command and signalling, adopted in its current form in 2023. The European Union Agency for Railways (ERA) maintains the specification and acts as system authority. It checks trackside ERTMS projects before contracts are signed, so that new installations follow the common specification. The same agency authorises vehicles for use in more than one member state, part of the wider interoperability framework.
How the system is built
The train carries an onboard unit, a computer that holds the train’s braking performance and tracks its speed and position. It calculates a braking curve continuously and applies the brakes if the train exceeds it. The driver reads speed limits and the distance ahead from a screen in the cab.
On the track, balises – transponders mounted between the rails – give the train fixed reference points for its position. The interlocking sets and locks routes, as it does in conventional signalling.
In the radio-based version, a radio block centre (RBC) sits between train and interlocking. It receives position reports from each train, checks the routes the interlocking has set and tells each train how far it may go. The radio link today is GSM-R, a railway standard built on 2G mobile technology.
ETCS has been issued in several versions, known as baselines. The 2023 specification introduced Baseline 4. Onboard and trackside equipment built to different baselines has to be checked for compatibility before a train is cleared to run on a line.
How a train gets permission to move
The permission is called a movement authority: a distance the train may travel, with the speed limits that apply along it. In ETCS application level 2, the RBC sends the movement authority by radio and extends it as the track ahead clears. The driver follows the cab display, and lineside signals are no longer needed.
In application level 1, balises pass the movement authority to the train as it runs over them. The train receives new information only at those fixed points, and the lineside signals stay in place.
Because the train supervises its own braking, trains can run closer together on lines designed for it. Capacity is the second argument for ERTMS, after interoperability.
Why deployment is slow
The third work plan puts ETCS on 10,600 km of the core network at the end of 2024, 17% of it. The legal target for 2030 is 62,960 km. Member states plan to equip another 28,000 km by 2030, which still leaves the core network short of the target.
Each line needs trackside equipment, and each train that runs on it needs onboard equipment. Until both are in place, infrastructure managers keep the old and new systems running side by side, and operators keep both on board. The Commission estimates that completing ERTMS on the TEN-T network will cost EUR 75–85bn for trackside equipment and EUR 10–15bn for onboard equipment.
The fleet is further behind than the track. About 13,600 vehicles are contracted or planned to receive ETCS on top of the 8,730 already equipped, according to the Commission. That is not enough to switch off the national systems. Retrofitting an older train means taking it out of service, redesigning parts of the cab and wiring, and obtaining a new authorisation.
Member states have also sought room to delay. They filed 163 requests for exemption from parts of the EU signalling specification between 2017 and 2023, against 25 between 2009 and 2015, according to a 2025 Commission report.
Prices have risen. The Commission said in 2025 that the cost of ERTMS products had doubled over five years, and attributed the increase to member states pursuing different multi-system approaches.
Some countries have chosen to replace their national system entirely. The Danish infrastructure manager is converting the whole main-line network and expects to complete the programme on all state-owned lines in 2033, according to a plan updated in March 2026.
What the law requires next
The TEN-T Regulation of 2024 sets three deadlines for ERTMS: the core network by the end of 2030, the extended core network by 2040 and the comprehensive network by 2050. National class B systems are to be phased out as ERTMS arrives. The regulation also requires radio-based ERTMS, defined as ETCS application level 2 without lineside signals.
The radio layer is changing as well. Industry support for GSM-R is expected to end around 2035. Its successor, the Future Railway Mobile Communication System (FRMCS), is based on 5G. The railway sector plans to include the first implementable FRMCS specification in the EU’s technical rules in 2027.
The first deadline, for the core network, falls on 31 December 2030. At the end of 2024, 83% of that network had yet to be equipped.