train signal pipe

例句：

1. 1. The train signal pipe is essential for signaling the arrival of trains at stations.
   火车信号管对于在车站发出火车到达的信号至关重要。
2. 2. The engineer inspected the train signal pipe to ensure its proper functioning.
   工程师检查了火车信号管，以确保其正常工作。
3. 3. The train signal pipe was damaged during the recent storm, which caused delays in the transportation system.
   最近一场暴风雨损坏了火车信号管，导致运输系统延误。