Plans to build a railway to connect Norway's two largest cities, Oslo and Bergen, were launched by Andreas Tanberg Gløersen in 1871. He proposed that the line run via Hallingdal and Voss and include two short branch lines which would connect to the two major fjord systems in the area, Sognefjord and Hardangerfjord. The narrow gauge Voss Line from Bergen to Voss opened in 1883, and the Bergen Line was completed as standard gauge in 1909. During the construction of the Bergen Line, the path that ran up Flåmsdalen was upgraded by NSB to allow access to the area around Myrdal. This road was used by horse carriages and later cars, becoming an important access route to the area, but it was too steep and narrow for heavy vehicles. The Hardanger Line, which connected the Bergen Line to Hardangerfjord, opened in 1935, and was the county's first railway to open with electric traction.