Modeling the CBTC railway system with ScOLA

Considering their increasing complexity, industrial systems are, in general, specified in a natural language. Especially transportation systems where the design phase results an ambiguous and laborious system specification. The objective of this paper is to present ScOLA, a formal modeling language based on scenarios and built on railway system specifications. Its novelty is based on its restriction to the core concepts of the specification and its multiple representations (textual and graphical), and also on its formal semantics. The language offers means to understand what the system was supposed to do and to be as well as to support a dialog with experts so to be sure that we got everything correctly. The methodology is applied on the railway automation solution Trainguard MT CBTC of Siemens.