This paper presents an application of the formal modelling and model checking toolkit mCRL2 and the model-based testing tool JTorX in the signalling domain. The mCRL2 toolkit is used to formally model the behaviour of a system at the core of signalling solutions: the interlocking. The model of the interlocking is validated through model-based testing. We use the mCRL2 toolkit to verify high-level safety properties of the interlocking software.