A nice expression of crowd etiquette. Even though they are forced into close proximity, they each must try to retain their own anonimity and keep to themselves.
I agree that the guy in the center really anchors the shot. The brighter clothes, the perfunctory stare at the viewer -- without him I think this would have been less interesting. He seems to be someone the viewer can identify with.
Great study of faces - no one seems very happy at all. My favorites are the guy about a third ni from the left, leanning his head back slight, as though he's trying to sleep standing up. And the half-face in the upper right. Since you've established the context of public transport by the windows, their stances, etc, you might want to cinsider cloning the text/images at the bottom, except for the bit on the far left.