To give it a literary and poetic quality.

1)Sometimes you need to emphasize the importance of one part more than the other parts. For example the act of " moving " is more important than the direction towards which the train is going.2)In some other cases we can guess from the context that the text is literary and the order of the sentence is changed in a poetic way.3)The last possibility is that the speaker simply is out of mood to make a grammatically strict sentence so gives the needed answer first :)