Thought I'd share, as a frequent passenger in Viewliner (single-level, Eastern long-distance train) sleeping car rooms:

In case the upper bed in the room rattles, the solution is to put all of the pillows, blankets and mattresses on top of the upper bed. Then push the bed up to the upper-most level, as close as possible to the ceiling, and lock it in place using the handle underneath the bed (i.e., normally you'd put the bed up for daytime use--just be sure that it has all of the pillows, blankets and mattress on it and that it's pushed as close to the ceiling as possible).

Rattling will stop.

Reason: the indention where the bed is locked in place is bigger than needed, so the bed can rattle because it moves up and down. If you have all of the pillows, blankets and mattress on it, they will push the bed to the bottom of that indention, if it's locked as close to the ceiling as possible, in the top-most position.

Hope this helps someone else.

Now on to find a solution to rattling doors...