While I agree that the grey sky is photographically undesirable (as some viewers pointed out), the negation of sky color makes the urban architecture appear very monolithic; but I enjoy the sense of powerful, foreboding ruin.

Actually, judging by the angle of the wheels, it looks like it was rolled up to the doorway and stopped there. That would definitely hint at it being a standby.

I wonder why they left it there, of all places.

One of the seats is trying to be different.