I am making a seven stall wooden roundhouse with the seventh bay being a machine shop area. The interior will be done. This diorama will have a turntable and a rail car shop. I will also have side track with various freight cars, water, sand, coal and ash pit.
My base for the roundhouse will be made of plaster simulating concrete once painted and will have pits in some of the bays. As for the turntable I will be purchasing one from Custom Model Railroads.