support
In Cable-Propelled Transit (CPT) support describes the guideway along which a vehicle travels. Support can either be provided from above the vehicle (in the case of Gondolas and Aerial Trams) or below the vehicle (in the case of Funiculars and Cable Cars).
Support can either by provided by rails or cables. In all but the rarest of examples, support from above is provided by cable and support from below is provided by rails.
Top-Supported
Gondolas, cable cars, and trams, as they’re often called, are all supported by cables, but the number of cables depends on the specific technology.
For example, a monocable detachable gondola (MDG) system has one cable for both propulsion and support, while the bicable detachable gondola (BDG) has two cables — one that is stationary and used solely to support the cabins and another in motion for propulsion. The 3S has three cables, two for support and one for propulsion.
MDG, BDG, 3S gondolas
CC Images by Flickr users minplanpac, www.planetjones.co.uk, robert.molinarius
Bottom-Supported
Bottom supported cable cars, cable liners, and funiculars are all support on rails but propelled by a cable. The most iconic example in North America would be the San Francisco cable cars and in Europe it is not uncommon to see funiculars transporting people up and down the side of a steep hill.
Support From Below By Rail
Historical Street-Supported Cable Car
Contemporary Cable Cars Typically Use Elevated Guideways
Creative Commons images by digika, Saopaulo1, and Perugia-City.com
