At the earlier stages, the vehicles were controlled by hard track lines without any network operation.

早期的城市轨道交通车辆一般由硬线控制，没有网络或者网络不参与控制。

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At the earlier stages, the vehicles were controlled by hard track lines without any network operation.

早期的城市轨道交通车辆一般由硬线控制，没有网络或者网络不参与控制。

youdao