A Centralised Interlocking System for Low-density Line Signalling with a Predictive Monitoring System

The methods adopted to provide cost effective signalling systems for the low-density lines have evolved over many years. In Japan, a typical conventional signalling system for single lines consists of three kind of equipment: centralised traffic control (CTC) equipment at the control centre and each station where an interlocking equipment is also located with a single line signalling equipment. This system structure thus has complex function layers that cause problems of capital and maintenance costs. In order to overcome these problems, we developed a centralised interlocking system (CIS), which provides all facilities available in both interlockings and a CTC system at significantly reduced cost while maintaining high levels of safety and reliability. The CIS, based on an electronic interlocking system technology, provides a direct interlocking between starting signals reading into each end of a single line section by means of the route locking logic. In addition to this normal interlocking logic, we produced a diversity train detection method in this development to reinforce safety at the single line signalling. Furthermore, in order to reduce maintenance costs we also developed a predictive monitoring system. The main reason is that we had to provide more satisfactory solution for the low-density lines. This system enables us to monitor condition of signalling infrastructure equipment such as track circuits, points, signal lamps, level crossings and power supplies at the control centre.