primary train diagram

例句：

1. 1. The railway company has released a new primary train diagram to improve the efficiency of its services.
   铁路公司发布了新的主要火车图，以提高其服务的效率。
2. 2. The primary train diagram clearly shows the route and schedule for the upcoming trip.
   主要火车图清晰地显示了即将进行的旅行的路线和时间表。
3. 3. The primary train diagram was used to guide the construction of the new railway line.
   主要火车图被用来指导新铁路线的建设。