Formalisation and simulation of operating rules using coloured Petri nets

Abstract

The operational rules safety assessment of rail systems is a key element of the rail success to improve the competitiveness. In this context, the goal of this paper is to present a process for a safety analysis of operating rules. The first step of this process describes the operating rules and their formalisation using coloured Petri nets by means of a systematic method. The second step concerns the simulation of the resulting nets to check their properties. A group of ERTMS (European Rail Traffic Management System) operating rules, stemmed from HEROE (Harmonization of European rail Rules for Operating) project concerning the departure of a train will be used as an example. These rules are "Departure", "Train preparation", "Permission of train movement authority" and "Written orders". Starting with a reminder of our systematic method of description based on coloured Petri nets (CPN), we show that the main advantage of this method is to standardize the rules description. Then, the properties of the resulting Petri nets are checked with appropriate tools, with a view to verifying liveness and to detecting possible deadlocks. Finally, we think that the process of formalisation and simulation will allow to check the consistency and the integrity of operating rules.