Not the only approach that's possible. There's quite a few lifts in France that pull a similar trick, but with only one cable.
They solve the problem by having the bar below the clamp be a flexible section, as the bar approaches the turn, a section a static rails forces the bar to rotate 30-40 deg around the cable, moving the protruding part of the clamp out of the horizontal plane. Then the cable passes around a large diameter wheel, also 30-40 from vertical, to create the turn.
Because both the bar and the wheel are both 30-40 degrees from vertical, the wheel meets the top of clamp, rather than the side, but cable can still make a turn in the horizontal plane. They're a little uncomfortable for the rider, because the bar you holding onto gets jerked left and right, but you make around the bend just fine, and without an elaborate 2 wire system.
I think the Chardonnet ski lift at Val d'Isère is an example of this type of lift, but I can't find any photos of the corner unfortunately.
For chair lifts, the lift at Ski Dubai has turn half way up, and their chairs are permanently clamped to the cable. For going up the chair just goes around the outside of normal wheel. For going down, to passes around an elaborate wheel with cutouts to make space for the chair clamp and bar. The running surface of this wheel is made up of smaller rollers, and there's a big friction break on hub. So a computer watches for incoming chairs, then slows the big wheel down as needed to align the chair with a cut out. You can catch a glimpse of this here (best video I could find)[2].
They solve the problem by having the bar below the clamp be a flexible section, as the bar approaches the turn, a section a static rails forces the bar to rotate 30-40 deg around the cable, moving the protruding part of the clamp out of the horizontal plane. Then the cable passes around a large diameter wheel, also 30-40 from vertical, to create the turn.
Because both the bar and the wheel are both 30-40 degrees from vertical, the wheel meets the top of clamp, rather than the side, but cable can still make a turn in the horizontal plane. They're a little uncomfortable for the rider, because the bar you holding onto gets jerked left and right, but you make around the bend just fine, and without an elaborate 2 wire system.
I think the Chardonnet ski lift at Val d'Isère is an example of this type of lift, but I can't find any photos of the corner unfortunately.
For chair lifts, the lift at Ski Dubai has turn half way up, and their chairs are permanently clamped to the cable. For going up the chair just goes around the outside of normal wheel. For going down, to passes around an elaborate wheel with cutouts to make space for the chair clamp and bar. The running surface of this wheel is made up of smaller rollers, and there's a big friction break on hub. So a computer watches for incoming chairs, then slows the big wheel down as needed to align the chair with a cut out. You can catch a glimpse of this here (best video I could find)[2].
[2] https://youtu.be/M7ghP4YTk3M?t=204