Why set this play on a train?Where is the train going? How does the train impact the narrative?

This is only a short answer space but I can give you a general comment. The setting of Dutchman is a subway car. All of the action is taking place beneath the surface of the city, thus it isn't "seen" in broad daylight. The imagery suggests this is the atrocious underbelly of the community in the city and of the soul that lies within each of us. It is a call to search out what is beneath, to make visible what is invisible, and to hold ourselves and others accountable.