ERTMS

ERTMS, or European Rail Traffic Management System, is a European initiative to standardize signaling and train control across national rail networks. The goal is to enable safe, interoperable cross-border operations, increase capacity, and reduce the costs of maintaining multiple national systems.

The system comprises two primary subsystems: ETCS, the European Train Control System, which provides train protection and movement authority, and GSM-R, the Global System for Mobile Communications – Railway, used for digital radio communications between trains and control centers. Together, ETCS and GSM-R form the core of the European signaling and control architecture, supported by cross-border coordination and harmonized certification processes. The program also aligns with broader railway safety and interoperability standards.

ETCS has several implementation levels that define how the system provides movement authority and how it uses trackside equipment. Level 0 represents no ETCS signaling and relies on national systems. Level 1 uses Eurobalises (in-track transponders) for position reference and can retain existing line-side signals. Level 2 relies on continuous radio communication via GSM-R, with movement authority transmitted directly to the cab, potentially reducing or replacing some fixed signals. Level 3 envisions moving block operation with full cab signaling and, in principle, no fixed trackside signals, though it is not yet widely deployed.

Deployment progressed across Europe with various cross-border corridors and new lines fitted for ETCS. The program is supported by European Union policy and railway-industry standards, including RAMS (reliability, availability, maintainability, safety) considerations and Baseline versions of ETCS, of which Baseline 2 is the most widely deployed, with Baseline 3 introducing newer features and security improvements.