Thanks for the comments, friends
@Erik – yes, the door hinges were built to be able to rotate. However, any hinge misalignment, coupled with the small gluing surfaces, makes them very fragile. It is all too easy for the glue to fail or, more probably, for the paper to delaminate locally.
@ Ciuttso – it would help, yes
The roofs were shaped in the same way as the closed cargo wagon. I’m not sure that the internal lights should look like this…