Gondolas of an aerial cableway:

The Maier family travels into the mountains with their two children. There the children ride the aerial cableway for the first time. Of course they want to know exactly from their father how such an aerial cableway works. Mister Maier explains:
The two gondolas are each hanging on a thick suspension rope made of steel. The gondolas can drive on this suspension rope similar to trains on tracks.
A second rope, the drag rope, firmly connects the gondolas to each other. When the two gondolas are about to start driving, a motor is moving the drag rope and so the gondolas start to move.