Development of Centralized Interlocking System for Railway Signalling and its Evaluation

Abstract

This paper describes the development of a centralized interlocking system (CIS) for railway signalling and its evaluation in terms of safety and availability. The CIS is applied to the Ibara-line (41.7km) connecting Soja, Okayama Prefecture, and Kannabe, Hiroshima Prefecture, which began operations at January 11, 1999. The objectives in developing a CIS were to provide all the facilities available in both interlockings and a CTC (Centralized Traffic Control) system at significantly reduced cost while maintaining high levels of safety and reliability.
The CIS is regarded as being divided into control center and lineside subsystems (see Fig.1). At the heart of the control center subsystem is the interlocking itself, which is a fail-safe multiple processor system. The lineside subsystem consists of the lineside data cable and trackside functional modules forming a fail-safe local area network.
The trackside functional modules are connected to the control center subsystem which control them by trackside data links using single mode(SM) optical fiber cables. For the CIS we developed a long distance data transmission system by means of SM optical fiber technology, permitting a direct link over 20km without using a repeater.
This system enables direct interlocking between starting signals reading into each end of a single line section. Furthermore, a train direction logic featuring a diversity train detection method that was produced in this development improves a safety level and a utilization rate in the single line signalling.