本文概述北京地下铁道行车指挥自动化系统。

A general description on the traffic control automation system of Beijing underground railways is given in this paper.

youdao

北京从前没有地下铁道。

There was not an underground in Beijing before.

youdao

北京从前没有地下铁道。

There was not an underground in Beijing before.

youdao