Waiting for things to dry/cure on my Boxfile Challenge piece has given me the time to think about other ideas.
I've wanted to build another layout for years but never had the time or space. I still haven't got that much time and I've got even less space but I thought I'd give it a go anyway.
My first thought was an Inglenook shelf for the operating interest but that would not give anywhere for trains to go round on their own or to run in new locos. Then I had a flash of inspiration - do both, one on top of the other!
The plan is for the circle/oval to be a narrow gauge mine track going along a mountainside before going underground and round a cavern with a lake in the middle - viewing the outside from one side and the inside from the other.
The Inglenook I'm not so sure, I really like some of the RNSD munitions depot stuff I've seen, so it might be something like that or maybe just a simple mine head.