When the train fire occur inside the tunnel with natural ventilation, how to control smoke spreading in order to ensure the safety of evacuation, is a worth deeply research project.

列车在自然通风隧道内发生了火灾，如何控制火灾烟气扩散以保证人员安全疏散，是值得深入研究的课题。

youdao

It provided for the train traffic order and ensured traffic safety. At present, the signal design of train control system needs continuous field tests to be improved.

目前列控系统的信号工程设计需要通过不断的现场试验进行完善，这样做的结果是会消耗大量人力和物力。

youdao

But also taking into account the military aspect of it, we've -- the object eventually, obviously, is to train Afghan national -- an Afghan national security force, army, and police, in order to ultimately transfer control to someone.

WHITEHOUSE: Press Briefing