Route safety verification of train control system by FTA modeling in SCADE

Train control system is designed for ensuring the safety of trains in rail operation, and route safety is a key problem of train control. Due to its safety-critical nature and complicated circumstance, train control system is a typical large-scale and complex system. To address the serious challenge of route safety verification in the system development, this paper proposes a novel method by integrating the function model and the fail-safe fault model of train control. According to the fail-safe principle of railway signaling, with the help of Scade formalism, route safety properties are expressed into a fault tree. The two models are investigated for compatibility and, interlinkage constrains are discussed. Then integration rules are defined to combine the fault tree model and the function model into one lumping model, on which the safety verification is performed using Fault Tree Analysis (FTA). To illustrate how to apply the approach, examples are carried out on a part of WuGuang high-speed railway line in China. The results show that the proposed method has a good performance and meets the critical requirements of route safety verification for train control system.