ETCS Level 2 is a digital radio-based train protection system. Movement authority and operational speeds are displayed in the cab for the driver. Apart from a few indicator panels it is therefore possible to dispense with conventional trackside signalling.

However, the means of train detection and hence the train integrity supervision still remains as part of the trackside capability. All trains automatically report their exact position and direction of travel to the radio block centre (RBC) at regular intervals. Train movements are monitored continually by the radio block centre. The movement authority is transmitted to the vehicle continuously via GSM-R together with speed information and route data.

The Eurobalises are used at this level as passive positioning beacons or “electronic milestones”. Between two positioning beacons the train determines its position via sensors (axle sensors, accelerometer and radar). The positioning beacons are used in this case as reference points for correcting distance measurement errors. The on-board computer continuously monitors the transferred data and compliance with the maximum permissible speed.