名词line修饰动词词组go through问题

It would have been so much easier if a train line went through here.

line是名词,线的意思,go through是动词词组通过，为何名词line可以修饰动词词组go through，合在一块翻成直通?

a train line 与 went through here 之间是主语和谓语的关系，你如何能觉得是名词修饰动词呢？自觉面壁思过吧！