I know that doors isn't very good, but classic house doors are too high and big. I can't build bus bigger, because it is going to be part of my town hall diorama and must fit the trolleys.
Usage of up side down hinges is good idea but it will be necessary to build bus higher, which I can't, or use red hinges (to fit red line), which I haven't.
The top doesn't lift off.
BTW thanx for for your comments.