When I first started watching this movie I was looking for some kind of subtle metaphors but it soon dawned on me that this movie was indeed about people on a train. The interactions between people are like those you can see any day on the street and when in occasion there is a slightly more interesting situation the dialogue becomes stilted and boring. Its not that I don't get how this film is trying to portray the way people interact, it's just that in this film they are very boring. If you want to see and analyse these kinds of relationships you'd be best to actually go out and buy a train ticket and look at the people on the train with you. It is realistic but you wouldn't go to a movie to watch a film about you sitting there watching the movie.