Peter Salts wrote:
>
> I would think that there would be enough opposing force (or weight) on
> the other side of the lift to prevent a large scale reversal of
> direction of the cable.  However, I'm sure that if the upside part had
> many passengers it may start sliding back as you described.

Not so.  This is the case on major jigback lifts (i.e., aerial
tramways) wherein the weight of the haul rope, hanger and cabin
on each side is so massive that the weight of the passengers is
almost inconsequential (for example, the massive tram at Palm
Springs CA -- 5300' of vertical and about a 2 mile slope length
(steep mofo) only uses about 400 of the 1000 available horsepower
to move the cabins, even with one fully loaded and the other empty.
A true counterbalance in that case.

Chairlifts are different. Chair, grip and hanger together only add up
to a few hundred pounds.  The mass of the cable on both sides, as
well as the carriers, does somewhat counterbalance the lift -- but if
you add about 600 pounds per carrier in passengers times the
number of carriers on the uphill line, the weight adds up.

Modern lifts have much more sophisticated anti-rollback
mechanisms than those built way back when....

skip


Skip King
Vice President/Communications
American Skiing Company
PO Box 450 Bethel ME 04217

"Live in the Outside"

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