ETCS Level 2.
ETCS Level 2 is a digital radio-based signalling and train protection system. It is also referred to as a cab signalling system because movement authority and signal aspect are displayed to the driver in the cab. Apart from a few indicator panels, it is therefore possible to dispense with track-side signalling.
However, 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. The movements of the trains are constantly monitored by the radio block centre. The movement authority, together with speed information and route data, is continuously transmitted to the vehicle via the GSM-R radio network.
The EuroBalises are used at this level as passive positioning balises or "electronic milestones". 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, the ETCS Level 2 cab signalling system is currently used on lines with speeds greater than 160 km/h. This train protection system is therefore used on the new Mattstetten-Rothrist line and in the Lötschberg base tunnel. The ETCS Level 2 cab signalling system is also used as a train protection system in the Gotthard and Ceneri base tunnels.