An aerial tramway is one or two set cables (called track cables), one endless loop of cable (called a haulage rope), and two passenger cabins. The fixed cables give support for the cabins. The haulage rope, by means of a grip, is solidly linked to the truck (the wheel set that rolls on the cables). The haulage rope is frequently driven by an electric motor and being connected to the cabins, moves them up or down the mountain.
Two-car tramways use a jig-back system: A large electric motor is situated at the bottom of the tramway so that it successfully pulls one cabin down, using that cabin's weight to help pull the extra cabin up. A similar system of cables is use in a funicular railway. The two passenger cabins, which carry from 4 to over 100 people, are positioned at opposite ends of the loops of cable. Thus, as one is coming up, the other is going down the mountain, and they pass each other midway on the cable span.
Some aerial trams have only one cabin, which lends itself better for systems with small altitude changes along the cable run.