In 1935, quarry workers at Porthmadog, North Wales were transported to the top via cable car, which required energy. To get them back down to the bottom at end-of-shift, a no-energy means was devised: A peculiar-looking board with a single large wheel mounted beneath, two smaller wheels at the nose, and a sort of outrigger arm.

If you're wondering how they controlled the speed, to avoid having a heavier man crash into a lighter man ahead of him, this lever at the top serves as a brake. When you pull it back, it connects to something beneath the board that contacts the track.

In this shot you can see all of the men ride down with their hands on the brake lever.

Nevertheless, apparently there were still crashes from time-to-time (though this appears to be staged for the camera's sake):

Full video with narration:

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