An extended system-theoretic hazard analysis method for the safety of high-speed railway train control systems

A high-speed railway train control system plays a key role in ensuring the safe operation of the trains. To ensure the safety of high-speed railway train control systems, it is vital to perform hazard analysis on them. In this context, this paper proposes a novel hazard analysis method which extends a previously reported system-theoretic hazard analysis method system-theoretic process analysis. The proposed method improves the standard system-theoretic process analysis to capture the temporal relations between inadequate control actions leading to hazards. These temporal relations are crucial for investigating the causes of hazards. To depict the temporal relations of control actions of high-speed railway train control systems, a new temporal logic called control action temporal logic is proposed first. Then based on this temporal logic, a new control action relation model is added into the process of system-theoretic process analysis. This model depicts the relations (including temporal relations) between control actions. In order to identify both the inadequate control actions and their temporal relations, an algorithm is designed and used. Finally, the effectiveness of the proposed method is verified through the hazard analysis on the Chinese Train Control System level 3.