Symbolic Model Checking for Interlocking Systems

Model checking is a fully automated technique for the analysis of a model of a system. Due to its degree of automation it is in principle suitable for application in industry but at the same time its scalability is limited. Symbolic model checking is one approach that improves scalability through the use of Binary Decision Diagrams (BDDs) as an internal data structure. This approach allows the user to increase the efficiency by customising the ordering of state variables occurring in the model to be checked. In the domain of railway interlockings represented as control tables, it is found that this task can be supported using an algorithm that has access to the track layout information. In our work we propose optimisation strategies that render symbolic model checking feasible for large scale interlocking systems. Our results yield a verification tool suitable for use in industry. DOI: 10.4018/978-1-4666-1643-1.ch013