Bi-Cable Aerial Lifts

TomWhite

As we discuss wind resistant aerial lifts, funitels, trams and 3S systems are at the top. These are expensive and complicated. I’ve wondered about 2S systems, even retrofitting chairlifts. The US has had few. I believe the original Vail Lions Head gondi was one. Leitner has revived the system. In the photos from Ropeways.net, the haul rope is on top and appears to ride over pulleys in the standard way. The static rope and grip are about 2’ below the detachable. There is no terminal photo. As the article suggests, this seems like the best of both worlds. More wind resistant than mono-cable, less expensive than tri-cable.

LEITNER: Latest bi-cable technology in Oberstdorf
The new "Nebelhornbahn" is the first of its kind

The exclusive innovations form a symbiosis of 1S and 3S technology. The bi-cable technology was combined for the first time with the Symphony 10 cabins. The modern bi-cable gondola lift brings the Nebelhorn into a new era and replaces the previous aerial tramway from the year 1977.

© Oberstdorfer-Kleinwalsertal Bergbahnen

https://ropeways.net/rn/berichte/bericht.php?news=7944&kategorie=1&klickpass=agh586zyf

LiftGuy

In 2S and 3S situations the ‘static’ or Track rope is on top and the haul rope is on the bottom with the gripping device- they are detachable.

TomWhite

That was my memory of rope locations. But in the third photo, the thinner track rope is on the bottom. The haul rope is also the cabin weight support. This system appears to simply use the static/track rope for stability.

LiftGuy

Tom- you've got it backwards.
"...the thinner track rope is on the bottom" - No, the track rope is always the larger and is on top as it supports the weight of the cabin. It is not attached to the cabin- it is attached to each terminal and is under tension so it can support the weight.
"...the haul rope is also the cabin weight support." - No, the haul rope is the smaller rope as it does not have to support the weight but just 'haul' or move the cabin. It attaches to each cabin with a grip, or in the case of reversible trams- socket connections.
Hope this helps.

TomWhite

Is that how you understand the photo? The larger rope and detachable grip is on top.

LiftGuy

I think you are being thrown off by the guiding roller being on the carriage instead of the grip. This picture should explain it. The grip is on the bottom, inverted, and the springs are to the outside.

TomWhite

Excellent, this picture is very clear. I was thrown by the other.

Do you know of any chairlifts that are 2S? Do you know if any lifts have been retrofitted to be 2S?

LiftGuy

Bi Cable technology isn't new, it's been around since the mining days in the 1800's.

Leitner has just rejuvenated and re-engineered the technology.
As for 2S chairlifts, many of the original doubles built after WWII were 2S, like this Heron at Berthoud Pass, CO built in 1947.

When mono cable systems (1S) came in to being, 2S technology became cost prohibitive. The advantage of the 2S and 3S is to be able to span longer distances because of the tensioned track rope. This also necessitates more robust stations that are more like Tramway stations than detachable chairlift stations which would make it very expensive to retrofit an existing installation.
Hope this helps.

TomWhite

Thanks.

lotsoskiing

Berthoud
Crazy design

Chuckstah

I may have ridden that lift. Skied there once in the mid 1980s, but don't remember anything unusual about the lift. Then again, at that point in time I paid almost no attention to what was dragging or carrying me up the hills, so long as it made it to the top.

TomWhite

This kind of lift seems like a good system to use where wind holds are a concern.

The CO ski history has the photo Lots has. There are others imbedded in the article showing the Herron chairlift. #1, 2, 7 and 8 show it. The 7th very clearly shows the bi-cable. I don’t know how to cut n paste those.
http://www.coloradoskihistory.com/lost/bpass.html

Below is a paragraph that discusses the lift. Further below is one of the shared memories.

Sam Huntington is credited with coming up with the idea to construct a double-seated chair lift, all the better to get skiers up the hill. He convinced Bob Herron, a Denver engineer, to make his ideas come to life, although Heron requested that the owners sign a waiver, in case the darn thing didn’t work. The Corporation took out, and was granted, a U.S. patent on the double chair lift in 1947. (The patent, however, was never enforced.) The lift began operating on February 17, 1947. The capacity of the lift was 400 per hour, a vast improvement for the day.

"I skied Berthoud Pass a few times while a student at CU Boulder, class of '52. I fell off that double chair once -- because I was enjoying
conversation with my seat mate and didn't see the hump of snow we were approaching. My tips dug in and I fell on my face. The chair was
so close to the snow that it knocked my hat off passing over me! Uninjured, except for my pride, I managed to roll to the side before the
next chair got to me.

TomWhite

I looked at CO ski history of Berthoud photo 7 again. It looks like a spring day in the 50’s. Skiers ascend ½ dozen stairs (sideways) to get to the loading platform. I presume this was the ski area’s way of dealing with deep snow by midseason. Snow could be pushed off the platform as the snowpack deepened. Today, some areas out west have adjustable height terminals. Oh, to have such an issue in the east!