The REVERSIBLE AERIAL ROPEWAY or JIGBACK
Cableways for passenger transport were initially developed on the basis of this very simple concept: two cabins are linked to the same hauling rope or carrying-hauling rope so that when you pull on the cable to make a cabin go up, the other one comes down, and of course they are made to arrive at the same time in opposite stations. This layout has the advantage of balancing non charged masses thus limiting the energy necessary to make the whole installation run. Carriers are linked to the hauling or carrying-hauling rope via a fixed grip and it is the variation in rope speed that makes the carriers slow down when approaching the stations and then stop. The major drawbacks of this concept lie in the transport capacity: only two cabins can be on the line and transport time is highly significant. In all the other concepts (except pulsed movement aerial ropeways) passenger loading time doesn’t penalize transport time. Like gondola lifts, either monocable or bicable reversible aerial ropeways exist.
Bicable reversible aerial ropeways
To reach adequate transport capacities (up to 2,000 p/h), it is necessary to use cabins with very big capacities (up to 200 people on two floors). Only bicable technology allows for this, thanks to the carrying ropes. Moreover, on this kind of installation the in-line speed can reach 12.5 m/s (45 km/h). This bi-cable technology shows its unique capabilities in sites where huge distances must be crossed and where placing a tower between stations (several kilometres apart) would be impossible. These outstanding installations greatly override the drawbacks.
These installations currently cost over 15 million euros. So it is not surprising that there are only about forty installations of the kind operating in France.
Monocable reversible aerial ropeways
Monocable technology limits reversible aerial ropeway performances. The absence of the carrying rope makes them useful only for small installations or particular devices (residential or temporary connections). The only exception is the reversible funitel that is able to be equipped with bigger cabins thanks to its two carrying-hauling ropes. This concept can be interesting to reach very windy sites where required transport capacities aren’t very important (about 2,000 p/h). A recent installation of this kind is operating in France and a second one is under construction.