In December 2025, the Belgian rail infrastructure manager Infrabel announced the full implementation of the train control system ETCS along its mainline network. A real milestone, which has only been achieved before by Luxembourg. Still, a fully functional ETCS network also raises operational questions. Infrabel took the time to explain to RailFreight.com the what, how and why of the implementation effort.
First things first. Belgium’s implementation of ETCS across the entire mainline network should not be understated. By comparison, Germany had only implemented ETCS on 1.6% of its network by the end of 2024. Additionally, the EU monitors ETCS implementation on TEN-T Core Network Corridors, which shows that other countries have not made nearly as much progress: Romania sits at only 2% of the 2030 implementation targets, France at 9%, and the Netherlands at 40%. Again, this only concerns selected corridors, not the entire mainline network.
Belgium clearly implemented ETCS at lightning speed. At the same time, the country did not have much choice in implementing the technology. The 2010 rail accident at Buizingen, which left 19 dead and 171 wounded, highlighted the shortcomings of the nearly one century-old national safety system. It could not prevent trains ignoring red signals.
A patchwork of ETCS Levels
Since Belgium already had in-house ETCS expertise after it had taken the first implementation steps in 2009, it opted to accelerate that implementation. In order to do cover the entire mainline network with ETCS within an acceptable timeframe and at a reasonable cost, Belgium chose to install a mix of three variants of ETCS:
- ETCS Level 1 Full Supervision (ETCS L1 FS)
- ETCS Level 2 Full Supervision (ETCS L2 FS)
- ETCS Level 1 Limited Supervision (ETCS L1 LS)
What is the difference between ETCS Level 1 and Level 2? Infrabel explains:
Every train operating under ETCS receives the necessary information about signals and the maximum permitted speed in the driver’s cab. With ETCS Level 1, both Full and Limited Supervision, this information is received via waves transmitted by beacons installed in the tracks and connected to the signals.
With ETCS Level 2, this information is not received via beacons, but via GSM-R masts located along the tracks. With Level 1, the information is received punctually, each time the train passes a beacon. With Level 2, a train receives information continuously.
Infrabel chose to implement ETCS L1 FS in places where that was already planned before the 2011 Masterplan, where ETCS L2 FS was not technically possible (such as in large stations), or on short sections between ETCS L1 FS zones. Otherwise, the infrastructure manager installed ETCS L2 FS, except on the more quiet sections. In the latter case, it installed ETCS L1 LS.
What is the difference between Full and Limited Supervision? Infrabel explains:
With ETCS Level 1, both Full and Limited Supervision, a train’s on-board computer receives information about the maximum permitted speed, whether the next signal is open or closed, the gradient of the tracks, etc. With Limited Supervision, the on-board computer receives this information over a shorter distance than with Full Supervision.
Furthermore, with Limited Supervision, this information is not visualised on the train driver’s screen. ETCS Limited Supervision is a system – a mode of ETCS L1 – that runs in the background. The train driver looks outside and follows the signals, as in situations without ETCS. If he or she does make a mistake, for example by driving too fast, the system intervenes and performs an emergency brake application. With Full Supervision, the train driver sees all the information on the screen in the driver’s cab.
The present day
That brings us to 2026. Fifteen years after the 2011 Belgian “ETCS Masterplan” and 2.8 billion euros later, the mainline network is ready for ETCS-only operations. Some 80% of expenditures went to interlocking, a base system for the control of switches and signals. Belgium is making the switch to the digital interlocking systems SmartLock and SIMIS W.
Milestone completed. Still, that does not mean that there are no more challenges on the horizon. In the coming decade, the 2G communication technology GSM-R should reach end-of-life status and be replaced with the 5G system FRMCS, which offers increased reliability, speed and higher levels of cyber security. This will require more expensive retrofitting and infrastructure work, just as Belgium has completed ETCS implementation.
Infrabel expects that we will end up with a dual system of both GSM-R and FRMCS, and so it does not worry that GSM-R will be defunct from one day to the next. The infrastructure manager is preparing to keep its GSM-R network operational for longer to retain its communications infrastructure.
Simultaneously, Infrabel is preparing GSM-R towers for FRMCS installation. However, not all equipment is commercially available or is even in existence, which means that planning for the switch is difficult. However, Infrabel adds that it maintains its own standalone rail fibre optic network, which offers security and a lack of interference. The “backbone” is there, so the migration to FRMCS has been “prepared” already. To complete the upgrade, Infrabel just needs to change the hardware of the communication system.
Who coordinates problem analysis and resolution?
Operationally, ETCS-only operations also bring about several challenges. Hans-Willem Vroon, director of the Dutch rail freight association RailGood, had earlier explained to RailFreight.com that ETCS operations in the Netherlands are not flawless. A key problem concerns independent investigation of incidents and the allocation of responsibility. The many involved stakeholders, such as part manufacturers, software developers, the infrastructure manager operators and train drivers make that process difficult. “As is so often the case in chains, the temptation is great for chain players to hide behind each other and for important players to disappear.”
The question is who, then, takes responsibility for the independent investigation of incidents or determines where operations derail?
Infrabel explains that it organises quarterly consultations with stakeholders by default. Moreover, the infrastructure manager says that it has traffic reports of all delays that occur on its network. If ETCS is involved in the incident, it consults with stakeholders to identify the problem. This, according to Infrabel, “goes quite well”. In other words, there is no formally appointed entity that takes responsibility, but these processes take place in good faith and in a cooperative spirit.
However, Infrabel does not expect system-breaking issues to arise. The use of technology is as watertight as possible with the help of certificates and homologation procedures. Still, not every supplier implements everything correctly – or identically to one another, despite certification – 100% of the time. There are some hiccups from time to time due to cost reductions, which can cause operational issues.