Towards a Common Ontology of Safety Risk Concepts for Railway Vehicles and Signaling

In the railway domain, different methods are applied for estimating safety targets (like SIL) in the subdomains of railway rolling stock (e.g., SIRF) and railway control, command and signaling (e.g., BP-Risk), respectively, which are referred to as railway vehicles and railway signaling for the rest of this paper. Such methods are also based on different terminology underlying different concepts used, e.g., as parameters. Even worse, similar terms often mean different concepts. This may lead to different risk estimates for these subdomains of the railway domain.