The small electric Torokko train runs for 20km/12mi between Unazuki Onsen and Keyakidaira, revealing superb landscapes and many bridges and hydroelectric plants built along the river. Clinging to the cliffside, the narrow railway track goes over bridges and through tunnels at a speed of 16kmph/10mph and was initially built to transport construction materials. The small train commands an exceptional view of the valley, with several stops on the way, in particular at Kuronagi Onsen.