事故造成繁忙干线客运列车脱轨18辆以上并中断铁路行车48小时应启动（）。

听力原文：W: Let's look at the survey on drug use and health we conducted yesterday.How reliable are these figures?M: They have a 3% margin of error.Q: What are the speakers talking about?(14)A．Newly-launched products.B．Drug users.C．Survey results.D．Public figures. 点击查看答案

发生在区间、专用线的火灾事故，有关单位必须在( )以内上报路局总值班室和主管业务处以及铁路公安消防部门。 点击查看答案