First point: Theme is catch the train not chase the train
second point: If you haven't played it through I dont think your judgement is valid to if it stands for the theme or not.
Third Point: The theme is integrated which you can even hear in open voice line where player is in the train and he is said to come back to train.
Fourth Point: I do really suggest playing a game through and through before passing any judgment as it unfair for not only for me as dev but also for everyone else.