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Next, the mountain tunnel was constructed. The tunnel was attached to the base, rather than the turntable, so that it could not rotate. A circular base was then attached to the tunnel so that it was above the turntable, but did not rotate with the turntable. Various decorations, such as the cactus, the station, and the wagon, were then placed on the circular base. The train was then placed on the turntable, so that it could rotate around the circular base and go through the tunnel. The motion of the mechanism is shown in the videos below.