On the Cloud-Enabled Refinement Checking of Railway Signalling Interlockings

Abstract

Railway signalling systems have received a great deal of attention from the formal methods community. One reason for this is that the domain is relatively accessible; another is that the safety analyses to be undertaken are often highly parallelizable. In this paper we describe a 'cloud interface' for the refinement checker, Failures Divergences Refinement (FDR), which has been motivated and validated by an approach to the modelling and analysis of railway signalling interlockings. In particular, the approach allows us to perform safety checks on systems consisting of billions of states.