Lots of 18" radius. From the pictures it looks like thanfully he had access on at least some of the outside, because no way can you reach the top from within that operating pit. Not to mention I am 20 years younger than the seller and wouldn't be able to squeeze through that 15" space to even get in there.
Zero operation, unless all you want to do is run mainline through trains. Is thre even a single siding anywhere besides the engine service?
It looks nice, and it may run well, but I know I would quickly grow tired of it the way it is. I like switching too much.
--Randy