Solving Europe's rail signalling challenge

How does ERTMS work?

The European Rail Traffic Management System (ERTMS) is designed to solve these issues. It combines two core components: the European Train Control System (ETCS), which supervises train speed, and GSM-R, the radio system that enables communication between trains and trackside equipment. Together, they create a common digital signalling standard.

By standardising signalling and communication technology across the continent, it promises safer and more punctual operations, greater network capacity, and smooth cross-border travel, which is one of the European Commission’s top three rail priorities. But according to Ramboll’s European Rail Atlas, progress has been uneven and with a mandatory deadline to equip the TEN-T core rail network approaching in 2030, most countries are also significantly behind target.

ERTMS is, in principle, a straightforward concept: one signalling standard for all European railways. In practice, deploying it across tens of thousands of kilometres of active rail infrastructure, while keeping services running, makes it extremely complex.

Ramboll's Rail Atlas data shows that, beyond a handful of front-runners, including Belgium, Switzerland, and Luxembourg, which have the highest network coverage, most European countries have barely begun ERTMS deployment. Denmark has committed to migrating its entire rail network to ERTMS Level 2 by 2033. But the largest networks including Germany, France, and Poland remain below 5% deployment, and most countries sit below 20%.

By the end of 2024, ETCS had been implemented on around 10% or approximately 12,400 km of the TEN-T network, while only 19% of the EU railway fleet had been equipped with onboard systems. Based on current planning, the deployment of ERTMS on the TEN-T core network will be achieved to only around 50% of the 2030 target.

Without a significant acceleration in delivery, this gap risks delaying the interoperability benefits that ERTMS is intended to unlock across the European rail network.

Why deployment is lagging and what makes it so challenging

The gap between ambition and reality reflects several deep-rooted challenges.

Scale and complexity: Replacing a signalling system on an active railway requires coordinating trackside infrastructure, onboard equipment, operational procedures, and staff training. For large countries, the task is enormous, and operating with mixed signalling can increase risk whilst reducing short-term capacity gains.

Technical and system integration: Beyond programme complexity, ERTMS deployment requires managing system compatibility, certification, and integration with legacy signalling across different technical baselines. The planned transition from GSM-R to FRMCS adds further complexity, as current systems must remain compatible with future standards.

Cross-border coordination: ERTMS only delivers its full interoperability benefits when deployed continuously across national borders. Yet cross-border sections remain some of the most poorly equipped parts of the network, precisely because they require two national infrastructure managers, two regulatory frameworks, and two funding streams to align. The EU's ERTMS Coordinator has called for stronger governance and tighter cross-border coordination to increase the rate of deployment along international corridors.

Financing gaps: Long-term infrastructure programmes require predictable, multi-year funding. Where this is absent, ERTMS deployment defaults to a piecemeal, project-by-project approach that misses the network-level logic and benefits.

Fleet and trackside must move together: Even where trackside infrastructure is upgraded, the benefits cannot be realised if trains are not equipped with ERTMS onboard systems. Aligning fleet renewal and infrastructure programmes, which operate on very different investment cycles, is one of the most underestimated challenges in the deployment process.

Training needs: Underestimation of the need for both operational and technical training may also delay ERTMS deployment.

For operators, this creates pressure on investment, maintenance, and certification. For infrastructure managers, it requires careful phasing to ensure upgraded corridors are supported by compatible rolling stock.

Despite the overall picture, two countries demonstrate what sustained commitment can achieve.

Belgium completed 100% deployment of ETCS across its national network in December 2025 - the first EU member state to do so. The achievement reflects over a decade of coordinated planning between Infrabel (Belgium’s national Infrastructure Manager), operators, and the regulator, underpinned by a national ETCS masterplan with clear milestones and budgets.

Denmark's approach is equally instructive. In 2009, the Danish parliament agreed a national green transport policy that included the full migration of the entire rail network to ERTMS Level 2. The programme covers both core rail corridors and regional routes and replaces traditional trackside signals with computer-based in-cab systems. In addition, training is being given to more than 4,000 employees in the national Infrastructure Manager, Banedanmark, as well as DSB and other operators.

What are 5 best practices for managing ERTMS deployment risks?

Ramboll's European Rail Atlas, combined with the findings of the EU's Third ERTMS Work Plan point to five priorities for countries seeking to accelerate and derisk deployment:

1. Embed ERTMS in long-term investment legislation:
   Piecemeal project funding cannot deliver network-scale transformation. Statutory multi-year frameworks as used in Austria, Denmark, and Norway provide the stability that industry needs to plan, procure, and deliver at scale.
2. Prioritise cross-border sections and high-traffic corridors first:
   The interoperability gains from ERTMS are greatest where trains cross borders or where network capacity is most constrained. Focusing initial deployment here will help maximise benefits.
3. Align fleet and infrastructure programmes:
   Governments and rail authorities should coordinate rolling stock replacement cycles with trackside deployment plans, so onboard and infrastructure upgrades happen in parallel rather than out of step.
4. Build governance capacity for corridor-level coordination:
   Cross-border deployment requires dedicated institutional structures to manage the technical, regulatory, and contractual complexity of equipping corridor sections that span multiple countries.
5. Invest in workforce training alongside technology:
   ERTMS changes how drivers, controllers, and maintenance team's work. Training and certification programmes need to be scaled up well in advance of deployment rather than after the fact.