intermittent and continuous ATP 101119 - irse.nl

• Level 2 is also based on conventional lineside signalling equipment, but is operated without linesidesignals. Instead an additional subsystem, called the Radio Block Centre (RBC) determines themovement authorities for the trains under its control and transmits these to the train where they areshown on the DMI. The system is based on continuous transmission using the GSM-R radio link.Balises are required only to provide position references and fixed information such as line geometry.This level is suited for main and high-speed lines.ETCS level 2• Level 3 systems of ERTMS/ETCS are intended to operate without lineside signals. Track basedtrain detection systems are made redundant by active reporting of the train position to the RBC. Thetrain reports its present position back to the RBC, which calculates the train end position by takingthe train length into account. As in level 2, the separation between trains is the task allocated to theATC centre called Radio Block Centre (RBC) but where in level 2 the resolution of thedetermination of the train’s position is equal to the length of the sections used in the train detectionsystem (e.g. track circuits or axle counters), in level 3 the resolution is mainly dependent on theaccuracy of the train’s odometry. Therefore level 3 systems can operate in fixed or moving blockmode. The absence of conventional train detection systems in level 3 requires trains to continuouslymonitor and report on their integrity, i.e. the fact that the train is still intact and therefore no cars arestill occupying sections of track about to be included in a following train’s movement authority. Untilnow however unfortunately no proven technical solutions for train integrity monitoring exist,especially for locomotive hauled freight trains and this, combined with the complexity of arriving atharmonised specifications for a level 3 system, have led Eurosig to postpone the development work onLevel 3.40