The Design And Realization Of The Software In Urban Rail Traffic Interlocking Systems

The computer interlocking system, which controls the devices such as signals and switches on wayside, is the critical part of the signaling system in urban rail traffic. It must be under the control of specific interlocking rules, in order to ensure the safety of the running vehicles. Automatic generation of the interlocking logic can improve the efficiency of logic generation and reduce unnecessary human errors. Besides, as the interlocking system has to exchange information with the other systems, it is important to use a communication protocol with high reliability, high efficiency and high safety. In this paper, the follow issues have been studied:1,Design and realize a safety communication protocol. Compared with the general TCP/IP protocol, a safety layer is inserted between the top application layer and the lower transmission layer. Several safety measures have been applied on this level to defense against the possible threats. Thus, the singnaling system can be switched to a fail-safe state when an unexpected failure or error occurs.2,Design and realize the software of the interlocking system. It has been divided into three parts:the station drawing software, the automatic generation of interlocking logic software and the interlocking execution software. The station drawing software draws the station by object-oriented approach and generates the station data file. Then, combined with the analysis of interlocking rules, the automatic generation of interlocking logic sofeware accesses with the data file and automatically generates the logic script file. The interlocking execution software periodically executes the interlock logic and communicates with the other systems.