Railroad companies employed thousands of workers to create the smooth, flat pathways required by trains.
铁路公司雇佣成千上万的工人来创建平通路所需的火车。
2
Can you imagine the individuals who make flat cars and rails and railroad engines and who construct and install the communication systems incidental thereto?
你可以想象一下那些操作平板车、钢轨和机车还有设计和构建交通运输系统的人们吗?
3
A fault in the wheel flat of a railroad car would threaten the safety of the car.