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。

youdao

Because the payload is much less massive than the control unit, the centre of rotation is close to the control unit.

ECONOMIST: Spaceflight on a shoestring | The