Research On Fallback Mode Of Moving Block System For Urban Rail Transit

The moving block system is one of development directions of signal system for urban rail transit. Normally, it is running in the ATC mode. But when loops, several spread-spectrum radios and centre control unit (moving block system with 'centralized' structure) fail, the system can not be running in the ATC mode. So, the concept of fallback mode is presented.In fact, the fallback mode is a simple operation mode of the moving block system in the non-ATC mode. The equipment, which provides this operation mode, is called as fallback system. It not only resolves the problem of operation when the moving block system is partially or totally inoperative, not also resolves the problem of temporarily transition before the moving block system puts into revenue service.Based on IEEE standard and domestic and overseas engineering practice, the fallback system is studied in detail. The definition, function, operational principle and design specification are presented. Based on two existed fallback schemes, a new fallback scheme with axle count and domestic interlocking system is presented. The analytic results of system capability, reliability and safety indicate that this scheme can meet design specification.