A Case Study: the RBC/RBC Handover Process

European Train Control System (ETCS) is a signaling, control and train protection system that is replacing the national, incompatible safety systems within Europe. ETCS consists of the on-board subsystem (composed of ERTMS/ETCS on-board equipment, the on-board part of the GSM-R radio system and speci c transmission modules for existing national train control systems), and the track-side sub-system (composed of balise, lineside electronic unit, GSM-R, radio block center (RBC), euroloop and radio in ll unit). In ETCS, the RBC is responsible for providing movement authorities to allow the safe movement of trains. A movement authority is generated by computing messages to be sent to the trains, where the messages are on the basis of information received from external track-side systems and information exchanged with the on-board subsystem. A route is divided into several RBC supervision areas. Here we consider the RBC/RBC handover speci cation. When a train approaches the border of an RBC supervision area, an RBC/RBC handover process takes place. For an e cient handover, communication between two RBCs is required when a train is about to move from one RBC supervision area to the adjacent one (see Fig. 1).