When building a good / guards van for the Swamp Dragon line, I decided to add a dragon compartement.
Some railroad companies had these for dogs. Nobody wants to have smelly dogs in coaches next to them.
From the outside, the compartment might seem a bit small. But have a look at the inside:

The dragons chewed up one of the cage bars and can move freely all over inside the waggon.
The model was constructed more or less from 2 / 3 mm cardboard, some coffe stir sticks and larger matches. Quite a few details are still missing. Have not yet decided, what colour I will paint the wagon.
Have Fun
Juergen