JF Ptak Science Books Quick Post
The difference between first and third class in an elevated train seems to be (1) a chair with arms, (2) a taller hat, and (3) a big moustache. Undoubtedly, there were actual creature comforts, though I suspect first class was meant to accommodate first-class people who would prefer not to be with not-first-class people, and enjoy the extension of that privilege in a comfortable seat.
What attracts me to this image is the way it rubs up against the accoutrements of modernity, looking like a piece of surrealist art. Since the image was printed in 1876 this would be "found-Surrealist art" as the existence of non-representational art was still 35 years away and the man who basically created the Surreal movement in NYC in 1924--Andre Breton--wouldn't be born for another 20 years. In any event, this is what this looks like to me, a piece of unintentional, out-of-context art with no contemporary name.
[Source, above and below: Scientific American, February 8, 1876. The image above is a cross section of the image below.]