train air signal stop cock

例句：

1. 1.The train signal stop cock was used to control the speed of the train.
   火车信号停止装置用于控制火车的速度。
2. 2.The engineer had to stop the train signal stop cock manually.
   工程师不得不手动停止火车信号停止装置。
3. 3.The train signal stop cock was responsible for stopping the train when it reached a certain point.
   火车信号停止装置负责在火车到达某个点时停止火车。