The Tinnoset Line was a 30-kilometer (19 mi) long Norwegian railway line that went from Tinnoset to Notodden in Telemark county. The railway was part of the transport chain used to transport fertilizer from Norsk Hydro's factory in Rjukan to the port in Skien. The railway opened in 1909 and was closed when the plant closed in 1991. The railway is sometimes mistakenly believed to be part of the Rjukan Line.