Very cool - I'd be tempted to crop away most of the LH side after the door seam; the passenger with the backpack doesn't, IMO, add anything to the image.
Outstanding photo, Tuna. I would not change a thing about it. To me, the way you cropped it shows the daily hustle and bustle of train rides. My eye went directly to the child, then floated across the rest of the image. This shot reminded me of my many hours of riding commuter trains here in Dallas.
My first thought was about cropping the left side. When I tried that, the image became "blah". I think the contrast between the sharpness of the girl and the other commuter brings her into focus and draws the eye. Her expression also plays a part.