page_title: Common Tunnel
section_title: West end
hierarchical_section_title: Common Tunnel / History / West end
caption_attribution_description: English: Nationaltheatret underground tram station, Oslo, Norway. Tram from Holmenkollbanen.
context_page_description: The Common Tunnel, sometimes called the Common Line, is a 7.3-kilometer long tunnel of the Oslo Metro which runs through the city center of Oslo, Norway. The name derives from the fact that all six lines of the metro use the tunnel, which runs from Majorstuen to Tøyen. The section has six stations, including the four busiest on the metro.
  The tunnel was first built as two separate tunnels which were later connected. The Holmenkolbanen company opened the western section of the tunnel from Majorstuen via Valkyrie plass to Nationaltheatret in 1928. In 1966, the Oslo Metro opened, including the tunnel from Tøyen via Grønland to Jernbanetorget. In 1977, the eastern end was extended to Sentrum, but the extension was closed in 1983 because of water leakages. In 1987, the Sentrum station reopened as Stortinget, and became the terminus of both the western and eastern lines. By 1993, the western end had been upgraded to metro standard, Valkyrie plass was closed, and the first trains ran through the whole tunnel.
  The section from Tøyen to Brynseng, although not completely located within the tunnel, is considered part of the Common Line.
context_section_description: In 1898, the Holmenkollen Line was opened as a light rail between Majorstuen to Holmenkollen. The terminus at Majorstuen was an inconvenience for passengers as most people were bound for the city center and had to change to the street trams. For the operator Holmenkolbanen, there were two ways to solve the issue. They could sign trackage rights with Kristiania Elektriske Sporvei to use the Briskeby Line to reach the city center. Alternatively, a tunnel could be built to an underground station in the city center. Applications for a tunnel were sent to the municipality in 1901. However, disagreements as to whether the tunnel was to be considered a railway or tramway halted progress; the city considered the line a tramway while the company considered it to be a railway.
  A new application was submitted in November 1907, which proposed a single track line to the intersection of Karl Johans gate and Fredriks gate, and was estimated to cost 1.5 million Norwegian krone (NOK). The plans drew criticism from city officials, who stated that the line would take passengers away from the existing tram line and that it would stimulate migration to the areas along the Holmenkollen Line in the neighboring municipality of Aker, thus reducing the tax income for the city. In 1909, Oslo City Council stated in a letter to the government that they were opposed to the tunnel. On 9 June 1911, the city council had nonetheless changed its mind, and voted to accept the tunnel if the terminus was moved to the intersection of Karl Johans gate and Ruseløkkveien, but this was rejected by the company. On 27 May 1909, Aker Municipal Council voted in favor of the tunnel, and on 9 June 1911 the proposal was passed by the Parliament of Norway. Both municipalities wanted the redemption right, which would allow them to purchase the railway at a later date, but this was instead given to the state. On 15 December 1911, Holmenkolbanen received a concession through a royal decree, which would last for 60 years from the date of opening.
  Construction on the central parts of the tunnel started in 1912. At the time, an agreement had not been reached with the municipality about the location of the terminus. In October, there was a landslip at Valkyrie plass, resulting in a cavity. Thirty properties sustained cracks and other damage, and the owners threatened Holmenkolbanen with a lawsuit to reclaim the cost of repairs. By October 1914, the tunnel works had been completed from Rosenborggaten to the statue of Karl Johan in the Palace Park (Slottsparken). The issue of the terminus was still not resolved, and work was therefore halted. Holmenkolbanen were planning on building the line through the city center, and therefore wanted the terminus at Fredriks gate, while the municipality wanted it at Ruseløkkveien.
  In 1915, the city launched a competition for a plan for city's light rail system. However, the invitations were not issued until two years later. The winner was announced in July 1918, and in September 1919, a municipal committee concluded on how the network should be expanded. Firstly, it proposed connecting the Lilleaker Line to Majorstuen. Secondly, it proposed a tunnel through the city center, from Majorstuen to Stortorvet and Vaterland, and onwards as an elevated line eastwards, along routes that closely resemble the current metro lines and the Ekeberg Line. From Stortorvet, a northern branch was proposed which would be built towards Kjelsås. Finally, the committee wanted a circular line north of the city center, closely resembling to the current Ring Line.
  The proposal forced the municipality to reconsider the terminus of the tunnel. The executive committee supported terminating the tunnel at Eidsvolls plass, but this was rejected by the city council on 13 July 1920. Holmenkolbanen convinced the municipality to establish a committee to look into the specific issue. In September 1921, the committee proposed creating a temporary terminus, following Holmenkolbanen's route, in the square behind the National Theatre (Norwegian: Nationaltheatret). This was under the 
caption: Tram at Nationaltheatret in 1928
exif: {"Image XResolution": "72", "Image YResolution": "72", "Image ResolutionUnit": "Pixels/Inch", "Image ExifOffset": "78", "EXIF ExifVersion": "0210", "EXIF FlashPixVersion": "0100", "EXIF ColorSpace": "Uncalibrated"}