in train

(of arrangements) well organized or in progress

（安排）妥當(dāng)，周密；在進(jìn)行中

an investigation is in train.

調(diào)查正在進(jìn)行中。

in someone/thing's train (或 in the train of)

following behind someone or something

跟隨（某人，某事）；隨后

train of thought

the way in which someone reaches a conclusion; a line of reasoning

思路；推理過(guò)程

I failed to follow his train of thought.

我沒能跟上他的思路。