基础汉语的解释： 一个从来没有去过大城市的人，坐火车来到了大城市，看到了繁华的城市夜景，这样的繁华场面以前从来没有见过。

imagine the picture you are a country boy who's never been to the big cities before, and now you get a chance to take the train to the place you're always dreaming of. be seated by the window, all the beautiful neon lights passing by.

就是，当一列火车开入一个城市，你会感觉这个城市很陌生，你会慢慢溶入这座陌生，慢慢发现这个地方很美，心理有着你爱的人，在城市的夜，看着这座，感觉如此繁华。。。

this is a song's words. meaning about :wen the train going to the strange city,that is i never seen rainbow.

It is the first line of the song "有没有人告诉你", right? In this context it expresses a feeling of loneliness and alienation. Getting apart with the person he loved and taking a train to a unfamiliar city, you can imagine that scene. The direct translation should be: "when the train entered this strange city, I found there were neon lamps around that I've never seen before".