On Vulnerability and Robustness Analysis of Railway Control System Using Digital Twin Model

As the risk of cyber attacks on critical infrastructure increases, railway systems, one of the significant modes of transport, also have the potential for cyber attack threats due to the increasing digitization and computerization. In the event of successful cyber attacks on railway systems, there is a high probability of sustaining significant economic losses and potential human casualties. Thus, it is imperative to consider the security of railway systems and maintain them in a secure state to mitigate the damages of cyber attacks. This paper proposes methods to maintain the safety of railway systems, assuming that the sensor incident caused the distance control to malfunction. Firstly, we enable the model train to perform distance control to reproduce the defects in distance control caused by sensor incidents. Secondly, we use Boolean networks to create a digital twin model created by integrating a model of the railway control program and a model of the rail system. We construct the state transition diagram from the entire digital twin model and identify a vulnerable state, in which the system transition is deadlocked. In the experimental system, this state appears as a train collision due to cyber attacks on the sensors at a merge point. Finally, based on the vulnerable state analysis, we discuss a robust state in which no accident occurs, even if cyber attacks on sensors occur.