上行线

例句：

1. 1. The train's tracks are straight and level.
   火车的轨道是直的。
2. 2. The engineer inspected the tracks before starting the new project.
   工程师在开始新项目之前检查了轨道。
3. 3. The tracks were damaged during the storm, which caused delays in the delivery of goods.
   暴风雨损坏了轨道，导致货物交付延迟。