Abstract: A laterally stable and self-turning wheel and rail assembly. The curved rolling surfaces of the wheels bear against curved contact surfaces of the rails such that centrifugal force causes lateral translation of the wheels on the rails, thereby increasing the effective rolling radius of an outside rail while decreasing or maintaining the same effective rolling radius of an inner wheel. The altered rolling radius causes the wheels to move along a curved path without slipping or sliding. Flanges are provided adjacent track turnouts so that guide members activated by a vehicle operator may contact the flanges to either maintain the vehicle in the same set of tracks, or switch the vehicle through the turnout onto a new section of track.