ETCS / ERTMS
ERTMS (European Rail Traffic Management System) is the EU standard for interoperable railway signaling. ETCS, its train-control component, transmits movement authorities to the onboard unit via trackside balises (Level 1) or GSM-R/FRMCS radio (Levels 2 and 3), continuously supervising speed and braking.
How it works
ETCS has three application levels. In Level 1, trackside balises transmit movement authorities to the train as it passes, working alongside conventional lineside signals. In Level 2, a Radio Block Centre (RBC) sends authorities continuously over GSM-R, and lineside signals become optional. Level 3 adds train-integrity reporting and moving-block separation.
The onboard European Vital Computer (EVC) compares the received authority with the train's position and speed, calculates a braking curve, and intervenes automatically if the driver exceeds it. ERTMS bundles ETCS with the radio system (GSM-R, transitioning to FRMCS) and operating rules.
Why it matters for security
ETCS Level 2 and 3 depend on a radio network and back-office RBCs to deliver safety-critical authorities, connecting onboard and wayside systems across national networks and multiple suppliers. The integrity and availability of that communication path, and of the RBC and interlocking behind it, are central to both safety and service continuity.
Related solution
Operating ERTMS across national rail networks
Protecting interoperable train control while preserving certified operation and cross-border service.
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