In reply to Simon4:
> I recall reading some notice board about the Vall£e Blanche cable cars saying that it would have been impossible for a horizontal, or nearly horizontal, cable car without the intermediate bracing from the rock outcrop. Something like 5.2 km, cannot be done without the intermediate anchor, though the Midi cablecar 2nd stage is itself a vertical mile, with a substantial horizontal distance. But seemingly the Vall£e Blanche is right on the limit of engineering for a cable car, especially a mostly horizontal one, quite apart from the point about how old and in need of maintenance it may be.
There is a mid station on a mini peak about 1km out from Cosmiques, it is manned but the cabin doesn't stop there they roll on through. I think there is some cabling off the peaks just after exiting the torino, which gives it a little more lift, after which it is long swoop down and up again, a few hundred metres of height loss.
The engineering limits are the weight of the cable, cabin and passengers across a tensioned wire. It exerts far more force on the anchors at each end than their individual mass alone. Tighter the line, ie nearer pure horizontal it goes, the forces increase massively. I think just to get to 120 degrees, you have double the force on either end.