D/F Rjukanfoss, prior to 1946 named Rjukanfos, was steam-powered railway ferry that operated between Mæl and Tinnoset on the Lake Tinn, Norway.

Owned by Norsk Transport, she was launched in 1909, expanded in 1946 and decommissioned in 1969.

Built by Fevig Jernskibsbyggeri in 1908–09, she was delivered 43 meters (142 ft) long, at 338 gross register tons.

She was equipped with two 150 kW (200 hp) steam engines, and capable of 9 knots.

The trackage was lengthened to 120 metres (390 ft) allowing 550 tonnes cargo in 16 cars, and the number of passengers increased to 250.