Unlike traditional vehicles, CPT vehicles do not have an onboard engine or motor. Instead, propulsion is provided by an off-board engine that moves a cable. Vehicles are equipped with a grip used to attach the vehicle to the cable. (In the case of a detachable grip system, such as an MDG, BDG, or 3S, the grip is non-fixed, so that cabins are detached from the cable in the station.)
So the vehicles are propelled by the cable which itself is propelled by engines and a bullwheel in a wheelhouse. Remember those old clotheslines with wheels? It sort of works like that.
A basic system consists of not one, but two bull wheels, one called the drive wheel, which is the one driven by the engine, and one called the return wheel, which is a free-spinning wheel that supports the other end of the cable. Deflection wheels are any wheels that alter (or deflect) the direction of the cable.
All images by CUP Projects unless otherwise noted.