My summer job consisted of a 40-hour work week from 12 am to 8:30 am. I cleaned subway cars. The entire interior, ceilings, walls, floors, everything. We had to get them done in time for morning service (first train leaves the railyard at 5:23 am, but it's sitting at the portal long before that). Sometimes we had to wait for the subway cars to get back from night service before we could start.
So what I'm trying to say is that I went H.A.M. cleaning subway cars for an entire summer. Paid well though, so I can't complain much.