Italian railways have adopted, among the first in Europe, the European Rail Traffic Management System/European Train Control System (ERTMS/ETCS) Level 2 on the new lines of the High Speed/High Capacity network. The system - based on a European standard - allows the movement of trains of different nationalities, based on information exchanged by the trackside and on-board subsystems, defined with a common language and managed with interoperable components. In particular, the standard defines how signalling information is to be exchanged between trackside systems and the trains, identifying the transmission techniques to be used and the format of messages.
With the installation of ERTMS/ETCS, the constraints for international traffic that resulted from the diversity of signalling systems currently in use in different countries have essentially been overcome.
The ERTMS/ETCS system provides the train driver with all the necessary information for instrumental guidance, continuously monitoring the effects of his/her actions on the safe running of the train and activating emergency braking in the case of train speed exceeding the maximum speed allowed for safety.
In the most common configuration, known as Level 2, the exchange of information between the ground and on-board subsystem is through the GSM-R radio channel, while the Eurobalise (fixed) transponders mainly function as position references. Through the radio channel, the SSB and in particular its intelligent core, the EVC, learns from the RBC (Radio Block Center, which centralises route freedom information) the "movement authorisations" for the train. An illustration of the process is given in the figure below.