Furuset Line - History

History

In 1948, the municipalities of Oslo and Aker were merged, and the new municipality started planning an expansion of the suburbs, among other places in Groruddalen. On 15 September 1949, the Planning Office For the Suburban and Underground Lines was establish as a division within the new municipality. The first specific plans were launched in March 1954, and consisted of four branches, including one on the south side of Groruddalen, which would be built to Furuset. The plans originally consisted of terminus in the city center at Grønlands torg, with a possible extension to Nationaltheatret, where the line would intersect with Holmenkolbanen's light rails serving Oslo West. However, it was quickly decided that the terminus would be Jernbanetorget, which served the Oslo East Station.

Construction of the Furuset Line, from Hellerud to Tveita, started in the mid-1950s. Landwork and electrical equipment was contracted to developers, while the trackage was done by the Planning Office. The original plans called for the use of 600 to 650 volt (V) direct current (DC) fed via a pantograph, to allow comparability with the western light rail. This was later changed to 750 V DC via a third rail. This was chosen to allow a higher diameter, and thus a higher ampere, and easier maintenance. The system also took into use cab signaling and moving blocks, which were cutting edge technology at the time, and had only been implemented on the Stockholm Metro in Europe by then. While the permitted headway on the common sections was set to 90 seconds, it was set to 120 seconds on the Grorud Line. The original plans called for a depot on each of the lines, including the Grorud Line, but this was later changed to a central depot at Ryen.

The first part of the line, from Hellerud to Haugerud, was opened on 18 November 1970, four years after the first part of the metro. The line was further extended to Trosterud on 15 December 1974, to Furuset on 19 February 1978, and finally to Ellingsrudåsen on 8 November 1981. The line took into use T1000 electric multiple units which could be up to six cars long. Originally the service terminated at Jernbanetorget in the city center. On 9 January 1977, the city center service was extended to Sentrum. However, this station was closed from 20 March 1983 to 7 March 1987, and reopened as Stortinget. From 20 November 1995, the trains on the Grorud Line continued all the way through the Common Tunnel to and continued along the Røa Line. In June 2010, the headway on the line was reduced from 15 to 7.5 minutes, with half the departures terminating at Stortinget. The reason was that the Røa Line was having its power supply upgraded, and Line 2 would only be able to run with three-car trains. From 6 November 2010, Line 1's eastern service was moved from the Lambertseter Line to the Furuset Line, thus giving eight services per hour along the latter. This was possible because of the upgrade of the Holmenkollen Line to metro standard. The Line 1 services replaced the extra services on Line 2.