Interoperability in Train Control

We consider the area of train control systems like the European Train Control Systems ETCS where several diierent scenarios are considered and accordant software components must interoperate eeectively in order to achieve the desired system behaviour. In order to specify corresponding problems for ETCS high-level Petri net techniques have been identiied as one of the most adequate formal speciication technique according to the state of the art. Unfortunately, Petri nets in the usual sense are not fully adequate to model such scenarios and to achieve interoperability. The new notion of open nets, developed within the DFG-Research Group Petri Net Technology, is most promising as a conceptual and formal technique for these kinds of problems. In this paper we study a simpliied version of a railway crossing control system with a few number of basic scenarios represented by interaction diagrams, which are modelled by open nets, called scenario nets. The interoperability of system components is speciied by suitable integration and composition techniques for open nets. These techniques should be a basis for in-teroperability in train control systems in general, especially for real problems in the area of ETCS.