|Opening||28 April 1957|
|Line length||8.4 km (5.2 mi)|
|No. of tracks||Double|
|Track gauge||1,435 mm (4 ft 8 1⁄2 in)|
|Electrification||750 V DC (third rail)|
|Operating speed||70 km/h (43 mph)|
|Highest elevation||165.5 m (543 ft)|
The Lambertseter Line (Norwegian: Lambertseterbanen) is a rapid transit line on the Oslo Metro system between downtown Oslo and Bergkrystallen. The line serves neighborhoods in south-eastern Oslo such as Lambertseter, and runs west of the Østensjø Line.
The first plans to build a tramway along part of the route of the Lambertseter Line were launched by Ekebergbanen. They had opened the Ekeberg Line in 1917, and in 1931 they had opened a branch, the Simensbråten Line. This 1.3 kilometres (0.81 mi) branch line was proposed extended along the route of the Lamberseter Line between Ryen and Brattlikollen. The terminus was planned at about Munkelia. The Ekeberg og Simensbråten lines were both suburban tramways in their own routes. However, the final section into the city center used street lines in mixed traffic. Since 1919, there had been plans to connect the Ekeberg Line with the Holmenkoll Line on the west side of town via an underground tunnel. Along part of the stretch, this connection was planned elevated. Due to the occupation of Norway by Nazi Germany 1940–45, all plans and construction of tramways were halted.
Following the 1948 merger of the municipalities of Oslo and Aker, it was decided that the Nordstrand area in the former Aker would be opened to large-scale construction of housing. It was decided that four lines would be built on the east side of town. The Lambertseter Line was given a new route west of Ryen, and would connect to the Østensjø Line at Bryn. These plans were passed by the city council on 9 December 1954, and also included the construction of the Grorud Line and an extension of the Østensjø Line from Oppsal to Bøler. In February 1956, it was also decided that the Lambertseter Line would be expanded to Bergkrystallen.
The 1954 decision was based on that both the Østensjø and Lambertseter lines would eventually be converted to rapid transit, after the Common Tunnel of the Oslo Metro opened from Jernbanetorget to Brynseng. Therefore, the tram line was built so that it easily could be converted to rapid transit: it was built for 3.2 metres (10 ft) wide trains, lean curves and no level crossings. At the time, it was presumed that the metro would be built with overhead wires, the same as the tramways. Between Munkelia and Bergkrystallen, the 245 metres (804 ft) Rabben Tunnel was built, and a branch line to the brick factory at Høyenhall. The station at Høyenhall was built with the high platforms that would be used on the metro; therefore the tram platforms were built as a low-entry expansion of metro platform. At Ryan and Brattlikollen, turning loops with radius 18 metres (59 ft) were built.
The length of the new line was 5.7 kilometres (3.5 mi), and total single-track length was 11.9 kilometres (7.4 mi), due to 500 metres (1,600 ft) of loops and other non-revenue track. To rectifiers were built, at Høyenhall and at Karlsrud. From Høyenhall towards the center of the city, the trams were to follow the Østensjø Line, merging at the bridge over the mainline railway. From Etterstad to the city center, the trams ran in street tracks in mixed traffic along the Vålerenga Line. To meet increased traffic and better the speed, large parts of the Vålerenga Line were rebuilt prior to the opening of the Lambertseter Line. This included an all-new section of track along Schweigaardsgate, which was also taken into use by the Ekeberg Line.
The Lambertseter Line was the first suburban line operated by Oslo Sporveier, and therefore the company copied the security procedures of Bærumsbanen, that operated the Kolsås Line and the Østensjø Line. The first operation on the Lambertseter Line with the SM53-trams was on 10 April 1957, after technical trials had been conducted with the Gullfisk-trams. Travel time from Jernbanetorget to Bergkrystallen was 28 minutes. The official opening happened on 28 April. The lines were trafficated with SM53-trams that had been in service up to five years with the company, and were bought specifically in mind to be able to operate the suburban line, in addition to street lines. In addition, school trams were operated with Gullfisk. At first, the Lambertseter Line was made part of Line 4, that connected onwards along the Kolsås Line. This was later changed so it only operated to Vognmannsgata from 19 June 1960. From 24 June 1963, the trams terminated at Jernbanetorget. Starting in September 1960, the loop at Ryan was taken out of service, and a depot for the metro was startet built at the site.
The last trams operated during the night between 17 and 18 May 1966, in preparation for the conversion to metro. The line was disconnected with the tramway at Høyenhall and instead to the new metro line that leads to the Common Tunnel. At Bergkrystallen the loop was removed and the tracks rebuilt. All the platforms were rebuilt to the platform height used by the metro. On 22 May, the Lambertseter Line opened as the first part of the Oslo Metro. It was connected to the Oslo East Station with a tunnel from Jernbanetorget to Ensjø, and onwards along the Lambertseter Line. In October the Grorud Line was connected, and in 1967 the Østensjø Line. With the upgrade, T1000 rolling stock was taken into use, along with automatic train control, step-free access with high platforms and a third-rail power supply.
Previously, the line was limited to three-car trains because of platform length constraints on the Kolsås Line in the west. To compensate, line 1 was extended to Bergkrystallen during peak traffic. These extra departures were removed with the temporary closure of the Holmenkollen line in March 2010. The resulting capacity reduction, with several trains still running with only three cars, resulted in overcrowded trains during the rush hours. The capacity crunch was caused by a lack of new (MX3000) cars, but Ruter faced criticism for not employing the older red car stock. Further deliveries of MX3000 have allowed several of the trains to be extended to six cars. An express bus line, line 4E, was also established to relieve pressure on the subway.
During 2010, the line will be renovated to meet the standards of the rest of the metro. This includes new sheds, new lighting and better accessibility, in addition to a general upgrade and renewal of the tracks and ballast gravel. At the time, the oldest tracks were from 1943, and the poor quality had forced the metro to operate with reduced speed, down to 30 km/h (19 mph) along part of the line.
|Wikimedia Commons has media related to Lambertseter Line.|
- Andersen, Bjørn (2007). "Lambertseterbanen 1957–1966". Lokaltrafikk 65: 4–11.
- Aspenberg, Nils Carl (1995). Trikker og forstadsbaner i Oslo (in Norwegian). Oslo: Baneforlaget. pp. 29–30.
- Trosvik, Kristin (22 April 2010). "Intim togtur for T-banereisende" (in Norwegian). Nordstrands blad. Retrieved 31 May 2010.
- Trosvik, Kristin (22 April 2010). "Refser T-banetilbudet" (in Norwegian). Nordstrands Blad. Retrieved 31 May 2010., Trosvik, Kristin (22 April 2010). "Det finnes fortsatt røde vogner" (in Norwegian). Nordstrands Blad. Retrieved 31 May 2010.
- "Forbedret vognkapasitet på linje 4/6 Ytterligere 2 6-vognstog i trafikk." (in Norwegian). T-banen. Retrieved 31 May 2010.
- Rutebok for Oslo, April 2011 edition, p. 316
- Trosvik, Kristin (30 April 2010). "Linje 4 får metrostandard" (in Norwegian). Archived from the original on 4 May 2010. Retrieved 4 May 2010.