a separate station on the west end. The latter solution was chosen, and Oslo West Station was opened along with the new line. Electrification and double track Built as a narrow gauge railway, the Drammen Line was converted to a dual gauge railway between 1917 and 1920. On 13 November 1922 the dual gauge was removed. The line from Oslo V to Brakerøya was electrified on 26 November 1922 while the line from Brakerøya to Drammen was electrified on 6 May 1930. The Drammen Line was the second railway line in Norway to be rebuilt to double track. The line from Oslo V to Sandvika was opened with double track on 26 November 1922 while the line from Sandvika to Asker was extended in three steps: Billingstad–Hvalstad on 24 July 1953, Hvalstad–Asker on 29 November 1955 and Sandvika–Billingstad on 9 November 1958. Double track further to Brakerøya in Drammen opened with the Lieråsen Tunnel, while the last part over the bridge into Drammen Station was finished in 1996. Lieråsen Tunnel The most significant shortening of the line came with the opening of the long Lieråsen Tunnel on 3 June 1973, part of a new line from Asker to Brakerøya. This concluded the double track to Brakerøya in Drammen, and shortened the railway by . Part of the old line, from Asker to Spikkestad, has been kept as the single-tracked Spikkestad Line, used by commuter trains. Oslo Tunnel After decades of planning, the Oslo Tunnel opened in 1980, extending the Drammen Line from Skøyen to the new Oslo Central Station, that replaced Oslo East Station. The former terminus of Oslo West Station was closed, and has since been converted into the office of the Nobel Peace Prize. The railway from Skøyen to Oslo V has been reclassified to the Skøyen–Filipstad Line, and is used for freight trains serving the Oslo Port. The former Port Line that connected the east and west stations was removed. Asker Line The Asker Line is an partially completed line that supplements the Drammen Line between Oslo and Asker. Construction started in 2001, with the first section from Asker to Sandvika opening in 2005. The section from Sandvika to Lysaker opened in 2011. The construction of the last section in the original plans, from Lysaker to Skøyen, was first postponed until after 2020, but in 2020, new planning started for a longer project extending all the way