Train detection and, therefore, train integrity supervision still remain in place at the track-side. All trains automatically report their exact position and direction of travel to the radio block centre (RBC) at regular intervals over the GSM-R network. The movements of the trains are monitored by the radio block centre. The movement authority is continuously transmitted to the vehicle from the RBC via the GSM-R network.

The Eurobalises are used as passive positioning beacons (electronic kilometre markers). Between two position beacons, the train determines its position through sensors (axle transducers, accelerometers and radar). The positioning beacons serve as reference points to correct any distance measurement errors. The on-board computer continuously monitors the transmitted data and the maximum permissible speed.

In Switzerland, a distinction is made for ETCS Level 2 between conventional speed areas and advanced speed areas. The difference between the areas is that conventional speeds are those up to 160km/h and advanced speeds are those between 160km/h and 250km/h.

The ETCS Level 2 train protection system for advanced speed areas is used on the Rail 2000 Mattstetten–Rothrist route, in the Lötschberg Base Tunnel and in the Gotthard and Ceneri Base Tunnels. ETCS Level 2 for conventional speed areas is used, for example, on the Brunnen–Altdorf, Biasca–Castione, Lausanne–Villeneuve or Sion–Sierre routes.