The Rjukan Line (), at first called the Vestfjorddal Line, was a Norwegian railway line running through Vestfjorddalen between Mæl and Rjukan in Vestfold og Telemark county. The railway's main purpose was to transport chemicals from Norsk Hydro's plant at Rjukan to the port at Skien, in addition to passenger transport. At Mæl the wagons were shipped on the Tinnsjø railway ferry to Tinnoset where they connected to the Tinnoset Line. The Rjukan Line and the ferries were operated by Norsk Transport, a subsidiary of Norsk Hydro.