Automatic Level Crossings: From Informal Functional Requirements´ Specifications to the Control Model Design

This paper deals with control design for automatic level crossings starting from their informal requirements´ specifications. The risks involved in these railway critical points explain the need of a high level safety control. The approach developed proposes a semi-formalization of requirements´ specification using VML activity diagrams, and the establishment of formal control models for the subsystems driving the level crossing, by means of time Petri nets. Finally, the global control model is built by integrating interdependence constraints between the elementary behaviors.