OBUs' Development and Maintenance of a Train Control System for Low Density Traffic Lines

This paper sketches the evolution of a train control system (TCS) and its on-board unit (OBU) for low density traffic lines. The train control system represents a distributed real-time control system consisting of on-board computers on each train, a traffic control center as well as a data radio system. The safety critical software components have been implemented in Ada95 and the system is constantly adopted for different industrial and research projects. The latest modifications dealt with the exchange of the communication mechanisms over the data radio system, the exchange of the data radio system itself and sensor replacements. These modifications have been performed within the realm of the EU funded research project SATLOC and tested in field.