Interlocking System for CBTC(Communication Based Train Control) System

In recent years, the environment of railways and the systems such as CBTC (communication based train control) have been changing. To respond the changes and the needs of customers, a UTCS (unified train control system) has been developed to realize a system that evolves with customers. Previous type systems consist of independent components such as ATC (Automatic train control) system, electronic interlocking system, and facility monitoring system, and there are a complicated overlap of system configurations and functions and difference in concept between the systems. On the other hand, the integrated train control system consists of horizontal layers such as function layer, network layer, and terminal layer. Therefore, the system has been developed to make it simple with no unnecessary redundancy and evolving to meet the needs of customers. In this paper, we explain a method that realizes the interlocking function for CBTC system in the function layer based on the concept of “securing a train travelling path” including path blocking and routing, and evaluate the safety of the method using STAMP/STPA.