Supervisory Control of a Railway Station for Providing and Verifying Safety and Avoidance of Trains Collision

In this paper, we deal with the problem of modeling railway network as a discrete event system using Petri nets in such a way that the theory of supervisory control may be applied to automatically control the signaling system. We provide a unified representation of railway networks in terms of stations and tracks, Normal trains and high-speed trains whose moving is in two directions and safety requirements in the model. The main specification such as running time per block, velocity and acceleration of the movement of trains is derived assuming zero slope in railway line. Places in petri net represent rail resources (the block) and tokens represent trains where is in the place means the railway block is busy. The supervisory control is implied in the model in based on railway line usage requirement included safety and non-stopping. In order to analyzing the safety and uninterrupted movement of trains, the illegal states is introduced for timed colored petri nets (TCPN). Creating timed holes in the network, it can be achieved the optimal scheduling. Then, the supervisory control not only should remove the respective states from the network but also it should control the train time scheduling result in several supervisory control per places (the blocks). The advantage of this method is the guarantee of safety without any rescheduling in operational level.