simple type of speedline.
zipline (Wikipedia)
Zip-lining in Costa Rica, January 2005
A zip line (or zip-line, zipline, zip wire, aerial runway (UK), flying fox (Australia and New Zealand), or foefie slide (South Africa)) consists of a pulley suspended on a cable, usually made of stainless steel, mounted on a slope. It is designed to enable cargo or a person propelled by gravity to travel from the top to the bottom of the inclined cable by holding on to or being attached to the freely moving pulley. It has been described as essentially a Tyrolean traverse that engages gravity to assist its speed of movement. Its use is not confined to adventure sport, play or tourism, but current usage tends to favour these meanings.