re: Bookshelf / hidden door

I’m curious about the hinges too. The hinge used on the doors at the end of the cars on the LIRR, on which I commute daily, are the beefiest piano hinges I have ever seen. They look like they will last the life of the car with no maintenance whatsoever. I imagine something like that would be necessary for this bookcase to ensure it doesn’t start to fall down over time.