The Rjukan Line (Norwegian: Rjukanbanen), at first called the Vestfjorddal Line, was a 16-kilometre (10 mi) Norwegian railway line running through Vestfjorddalen between Mæl and Rjukan in Telemark. 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 30 kilometres (19 mi) on the Tinnsjø railway ferry to Tinnoset where they connected to the Tinnos Line. The Rjukan Line and the ferries were operated by Norsk Transport, a subsidiary of Norsk Hydro.
Construction of the line started in 1907, and it opened two years later. It became the second Norwegian railway to be electrified in 1911. It experienced heavy growth, and had fifteen electric locomotives in use. During World War II it was the scene of the Norwegian heavy water sabotage. After the 1960s production declined, and the railway was closed in 1991. It was kept as a heritage railway.
The Telemark power-based industry started in 1902 when Sam Eyde, along with Norwegian and Swedish investors, bought Rjukan Falls—establishing A/S Rjukanfos on 30 April 1903. The same year, on 13 February, Eyde and Kristian Birkeland had met and started working on refining the electric arc to produce an electric flame; allowing Eyde to complete his process of converting air and electricity into fertilizer. On 19 December 1903 Det Norske Kvælstofkompagni was founded, followed by Det Norske Aktieselskap for Eletrokemisk Industri (today Elkem) in 1904; both were in part owned by the Wallenberg family, Stockholms Enskilda Bank and Banque de Paris et des Pays-Bas.
Rjukan is a town and the administrative centre of Tinn municipality in Telemark, Norway. It is situated in Vestfjorddalen, between Møsvatn and Lake Tinn, and got its name after Rjukan Falls ('the smoking waterfall') west of the town. The Tinn municipality council granted township status for Rjukan in 1996. The town has 3,386 inhabitants (Jan. 2007).
Rjukan was formerly a significant industrial centre in Telemark, and the town was established between 1905 and 1916, when Norsk Hydro started saltpetre (fertilizer) production there. Rjukan was chosen because Rjukan Falls, a 104-metre waterfall, provided easy means of generating large quantities of electricity. The man with the idea to use the Rjukan falls was Sam Eyde, the founder of Hydro. It is estimated that he, together with A/S Rjukanfoss (later Norsk Hydro), used about two times the national budget of Norway to build Rjukan and that there were approximately 12,000 workers (Rallare) from Sweden, Denmark, and Finland, as well as Norway building the factories and the town.