9 replies to this topic

[pete643]

I noticed on the Leitner website that they have a section on bicable gondolas. They work somewhat like trams, with a haul rope and a track rope.

What is the point of that? Is there some big advantage that outweighs the extra complexity? Also, what happens if a gondola derails? Is there some sort of detection system that can sense this?

I was on one in Austria, but it was very old, with the haul cable hanging way down and rolling on sheaves about a third of the way down the tower. When a car went past the tower, it lifted the rope off the sheaves, and then the rope set back down on the tower, guided into the sheaves by two metal arms sticking out the side of the tower.

[SkiBachelor]

The advantage of bi cable gondolas is that they can go over long spans and go up steep sections.

[KZ]

They probably have a bit better wind stability as well, but mainly for the reasons cameron said.

[SkiReg]

Bi-cable systems have several advantages.

1. They have a much higher capacity per hour than trams, similar to detachable mono cable systems

2. They are much cheaper than trams but more expensive than single cable gondolas

3. They can handle longer spans than single cable systems, although not as long as trams

4. With the track rope, they have a much higher stability factor than a single cable installation

With these advantages, the bi-cable system is making somewhat of a comeback in Europe. I believe that Leitner built six or so such installations last year.

[edmontonguy]

One of if not the last Bi-Cable Gondolas in North America is the Banff Gondola. It has a very Steep Liftline and it is obvious how far the spans are on the lift.
http://www.skilifts.org/nwsforum/index.php?showtopic=288

[pete643]

Interesting stuff. But, what happens if/when one of the cabins derails from the track cable. Does the haul cable hold it up? The pictures of the Banff Gondola show what seems to be just two sheave wheels on each cabin, without any type of protection against derailments.

I know many years ago at Vail on the old gondola, something went wrong with the track cable (fraying I think), which caused one or two cabins to fall off and crash into the ground.

What is the safety equipment on bicable gondolas to prevent/take care of derailments of individual cabins?

[edmontonguy]

The sheave wheels (there are actually 4 of them) have deeper groves than standard sheaves. I do not believe that there is any sort of cable catcher meachanism. Part of what is responsible for keeping the wheels firmly on the track cable is the weight provided by the significalty slackened haul cable which the cabin grips support. The Grip does not encompass the cable like a moncable lift so the odds are in a derailment the haul rope would become detached from the grip. Due to increased horizontal stability it is more likely to become derailed due to mechanical failure rather than some sort of meteorlogical phenomenon.

[vons]

Bi- Cable systems also tend to be very energy efficcent. In regards to the vail accident in 76 a combination of towers improperly placed and the track cable too slack caused the outer layer to fray at tower six due to the too great of bending stress on the cable. The lift was rebuilt by VonRoll with new grips altered towers and tower locations, modifide terminals etc.

[SkiliftMaster]

Ya i did i arial tram project. I was reaserchin and the banff tram used to be used for getting up the mountain. They used to have a trackter that toook you up!

[Aussierob]

Another advantage is less tower maintenance. All the moving parts are on the cabins, not on the towers. (except for a few floating sheaves)