At present, the train signal systems include the fixed block system and the moving block system.

目前列车信号控制系统中有固定闭塞系统和移动闭塞系统。

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This paper describes the origin, definition and function of fallback mode of moving block system for urban rail transit.

介绍城市轨道交通中，移动闭塞系统的后备模式的由来、定义及其功能。

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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.

但是当环线、多个扩频电台、中央控制单元(“集中式”移动闭塞系统)等设备出现故障时，系统将无法工作在ATC模式下。

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