The 16 km long railway was operational between 1927 and 1991. In Mæl cargo (consisting mainly of chemicals produced in Hydro's fertilizer plant) was loaded onto ferries for transport across the lake to Tinnoset. In 1944 a steam ferry Hydro was sunk on the way from Mæl (as a part of Norwegian heavy water sabotage) with a cargo of heavy water for Nazi nuclear weapon project.