Centralized Traffic Controlling System for Sri Lanka Railways

This paper discusses the design of a centralized control and monitoring system for railway traffic that can be implemented on top of the existing control logic (interlocking system) of Sri Lanka railways. The overall solution comprises of a central server system and databases with redundancy, relay house hardware unit (with embedded Ethernet and a custom communication protocol for microcontrollers) to interface with the relays of the interlocking system, Dispatchers Controlling Interface for remote monitoring and controlling, and a TCP/IP network which interconnects all the above mentioned components of the total system. The current centralized traffic control (CTC) system in Sri Lanka, located at Maradana, was implemented in the year 1985. This has manually operated switch boards, a relay based operation (separate relays for controls and indications) having every switch hardwired to the relays which are located along side the railway tracks via a copper medium. The main features of the new system are flexibility, reliability, fault isolation and robustness. The product adds flexibility to the user interface and automated report generation increases the efficiency of administrative purposes. User friendliness is a major concern that has been addressed in the development of the solution so highest priority was given to the users feedback and requirements. On top of this the user interfaces were designed to suit the existing railway signaling conventions to minimize the resistance to change. Static redundancy is provided at the heart of the system which is the server in the hot standby mode. These features minimize the probability of system failure hence increases the reliability of the system. Since this system uses TCP/IP as the main communication protocol, any type of physical media can be used for the communication network. The new solution was successfully tested in the test track in Dematagoda with the presence of senior officials of Sri Lanka railways and proved its potential for implementation.