Simulation of a complex railway station with a Petri Nets based interlocking model

Main topic of the research is the study of complex railway networks with different infrastructure configuration, diverse technological level of safety systems and various operating programmes, in order to evaluate their effects on the carrying capacity of the network. The work was directed on the development of a reliable model to simulate in real time the behaviour of the railway network, including the interlocking components and the signalling system, coherent with the safety logic, corresponding to a generic operating programme. Main tools and criteria used to develop the model are: - Extended Petri Nets Language - Object-oriented logic - Flexibility and re-usability Using Artifex hierarchical, extended Petri Nets language to map the structure of railways networks, it is possible to obtain an object-oriented simulation environment. Four classes of infrastructure components are defined: track circuits, points, block signals and advanced signals. Whole network is obtained by connecting objects belonging to these basic classes; this logic allows to model networks of any size and layout by simply reiterating the same approach. The model has been applied at first to a simple station, and relevant improvements followed after that, especially in the modelling of the “operating programme”. The station currently simulated is of medium complexity, with 9 tracks and 34 points. This allows the trains to follow 63 different routes inside the station, coming from 6 double track lines. The model allows the analysis of trains’ running time with any possible timetable; stochastic delays of trains are also applied. Further steps for development of the simulator are the user interface, in order to enable low experienced users to create networks and define timetable and train properties