Formal Verification of the Danish Railway Interlocking Systems

Abstract

In this paper, we present a method for formal verification of the new Danish railway interlocking systems. We made a generic and reconfigurable model of the behaviors and high-level safety properties of non-collision and nonderailment. This model accommodates sequential release – a new feature in the new Danish interlocking systems. Instantiating the generic model with interlocking configuration data results in a concrete model and high-level safety properties. Using bounded model checking and inductive reasoning, we are able to verify safety properties for model instances corresponding to railway networks of industrial size