It’s a G scale set. They are known for gardens and outside use. The room in the front of the tank has a single track that goes around the room. The room behind the tank, with the sump I’m working on, has the track that switches into 4 through sidings. So I can have a total of 4 trains. When one train goes behind the tank another one comes out and does a loop around the fish room. The plan it to have the trains alternate directions coming from behind the tank.I know this is a fish forum but I would very very much like to know more about the model railroad.