The Østfold Line () is a railway line which runs from Oslo through the western parts of Follo and Østfold to Kornsjø in Norway. It continues through Sweden as the Norway/Vänern Line. The northern half is double track and the entire line is electrified. It serves a combination of commuter, regional and freight trains and is the main rail corridor in the south of Norway. The Follo Line runs parallel to the Østfold Line in tunnel. The Eastern Østfold Line branches off at Ski Station and runs before rejoining at Sarpsborg Station.
The line opened as the Smaalenene Line () on 2 January 1879. Stations were designed by Peter Andreas Blix. It was the first railway in Norway to predominantly build bridges and viaducts with iron. The line underwent upgrades from 1910 through 1940 in which the section from Oslo to Ski received double track, the permitted weight and speeds were increased and the line was electrified. From 1989 to 1996 the section from Ski to Sandbukta received double track and the maximum permitted speed increased to . Work since 2015 been under way to upgrade most of the line to high-speed, with the new tracks at least as far as Halden by 2030.
Route
The Østfold Line runs from Oslo Central Station through the counties of Oslo, Akershus and Østfold to the Norway–Sweden border at Kornsjø, covering a distance of . The line generally follows the west shore of the Oslofjord until Halden, where it passes through major towns of Ski, Ås, Vestby, Moss, Fredrikstad, Sarpsborg. The line is standard gauge and electrified at . It is double track from Oslo to Sandbukta north of Moss, a distance of , as well as past Rygge Station. There are three railway stations and three freight terminals along the line. At Kornsjø the line continues through Sweden as the Norway/Vänern Line.
The term Østfold Line is most commonly used to describe the section from Oslo via Moss to Kornsjø. This is sometimes also referred to as the Western Line. Both uses exclude the section from Ski via Askim to Sarpsborg, known as the Eastern Line. At other times Østfold Line is used to refer to the entire network, both via Moss and Askim. Sometimes Western Line is used to only describe the section from Ski via Moss to Sarpsborg. Although the eastern and western branches were initially planned as equals, the western has become dominant due to it always having had a higher standard and serving all through trains.Langård & Ruud: 151
At Loenga in Oslo the line branches, the main part heading to the Central Station and the Loenga–Alnabru Line branching off to Alnabru Freight Terminal. This section is only used by freight trains.Bjerke & Holom: 60 The Eastern Østfold Line is and runs from Ski to Sarpsborg via the municipalities of Tomter, Hobøl, Eidsberg, Mysen and Rakkestad. Normally only serving commuter trains, it can be used as a bypass when needed.
Oslo−Halden via Moss Østfold Line turns southward right after Oslo Central Station and runs alongside Bunnefjorden`s shoreline until Ljan, where the route takes a more eastern inland corridor to Moss. This means following flat valleys in north-south direction, passing Kolbotn, Ski and Vestby. In Moss Østfold Line again reaches Oslofjord shore but soon deviates eastward and, for the second time, crosses over in the coastal hinterland, this time to Fredrikstad. From there on, heading northeast, the line uses the Glomma valley to Sarpsborg, bridges the river, turns southward and reaches Halden after running through mostly flat terrain in southern Viken (county).
History
Planning The lack of early interest in a railway in Østfold was caused by the ice-free Oslofjord and the perceived non-necessity of build a line where a suitable waterway already existed.Langård & Ruud: 17 Proposals for a railway through the county then known as Smaalenene were first launched with two independent letters to the editor in 1866. They exemplified the debate which would follow, with one proposing a route along the coast through the larger coastal towns, while the other proposed an inner route via Askim and Rakkestad. Preliminary surveys were carried out the following year, which also investigated two routes to the Swedish border, one via Tistedalen and one along Iddefjord. The government was at first less enthusiastic, in part because they were concerned that no line would be built on the Swedish side.Langård & Ruud: 19
By 1872 the disagreement over an interior or coastal route was raging and a compromise was proposed in which the line would be built with two branches.Langård & Ruud: 20 The government recommended a twin-armed line on 5 April 1873 and was approved in Parliament on 5 June. Detailed surveying was led by Carl Abraham Pihl and concluded on 31 March 1874. The route was still controversial, especially relating to how Fredrikstad should be served. The main line could be shortened by if the town was served with a branch line.Langård & Ruud: 22 With increasing cost estimates, Parliament decided to reduce the standard on the Eastern Line. There was also a controversy if that line should bypass Mysen.Langård & Ruud: 23
In Halden there was a significant opposition to the line, as there was worry that it would capture lumber traffic which would otherwise run to Halden. Traders and politicians there were more concerned with being connected with the Swedish province of Dalsland, from which a large part of the town's lumber export originated. To secure the Swedish part of the link, the Dalsland Line was built as a private railway with eighty percent Norwegian capital and its head office in Halden.Langård & Ruud: 25
Construction
Construction commenced in 1874, initially only on the section from Oslo to Halden. Work was subdivided into eleven sections on the Western Line and four on the Eastern Line. The former received a rail weight of 30 kilograms per meter (60 lb/ft).Langård & Ruud: 24 Work on the Eastern Line did not start until 1877. It received a track weight of only 25 kilograms per meter (50 lb/ft). A recession hit in 1877 and the government stopped all construction for a period, initially only continuing it on the Western Line.Langård & Ruud: 26 Most of the workforce were Swedish immigrants. Groundwork was conducted directly by the railway based on accords, with the track was laid by contractors.
The Østfold Line was the first railway in Norway were all bridges were built with iron. This allowed for the construction of viaducts at some places, which changed the mass balance allowing the line to follow a better gradient. Two of the most prominent were the Ljan Viaduct and the Hølen Viaduct. The latter was the first in the world to use the pendulum pillar principal. The bridges and viaducts were all designed by Axel Jacob Petersson.Langård & Ruud: 30
The Western Line from Oslo to Halden was taken into revenue service on 2 January 1879.Langård & Ruud: 50 However, the official opening did not take place until 18 July. By then the rail connection onward to Gothenburg had been completed.Langård & Ruud: 54 Construction of the Eastern Line was delayed and was opened in stages between 18 July and 24 November 1882.Langård & Ruud: 58
Early operations The first rolling stock consisted of eight NSB Class 9 steam locomotives for passenger train, three NSB Class 10 units for freight trainsLangård & Ruud: 44 and two NSB Class 14 locos.Langård & Ruud: 46 Passenger cars were at first 60-compartment coaches.Langård & Ruud: 47 A commuter train service was introduced from Oslo to Ljan Station from 1883, allowing the areas of Nordstrand to open up to large-scale housing.Langård & Ruud: 56 The railway allowed for faster postal services and the trains carried markers with the weather forecast, which was announced at the stations.Langård & Ruud: 59 A direct international train service was not introduced until 1 July 1886, when a direct service to Gothenburg and Hamburg was introduced. Travel time to Copenhagen was at that time twenty and a half hours. The following year sleeper cares were introduced.Langård & Ruud: 62
The commuter traffic increased and in 1893 a new commuter station was opened at Kolbotn.Langård & Ruud: 78 Two branch lines were built from Sarpsborg. A branch to Borregaard opened in 1891 and the Hafslund Line opened eight years later.Langård & Ruud: 80 To avail the problem in Oslo with human manure, depots were built at Drømtorp, Ås and Vestby to give farmers access to the resource. Manure trains ran until 1929.Langård & Ruud: 82 Construction of interlocking systems started on some of the busiest stations in 1897, although fail-safe functionality was not available until the 1920s.Langård & Ruud: 89 A faster inter-Scandinavian service was introduced in 1900, cutting travel time to Copenhagen to 16 hours and 20 minutes.Langård & Ruud: 92 The higher demands caused the railway to order nine new NSB Class 27 locomotives, delivered between 1910 and 1916, which allowed the maximum speed on the line to increase from .Langård & Ruud: 98 NSB introduced Ea 1, an accumulator electric locomotive, on local services between Fredrikstand and Skjeberg in 1916, where it remained in use until 1920.Langård & Ruud: 108
Line upgrades As the main international railway out of Norway, the Østfold Line had some of the highest demands for speed and axle loads. In an effort to increase train weights and speeds, the Norwegian State Railways approved an upgrade plan in 1910 which was initially to be completed by 1919. All bridges and track was to be upgraded to tolerate a higher train weight.Langård & Ruud: 93 The break-out of the First World War led to material and funding shortages,Langård & Ruud: 94 and the upgrades were not completed until a new Sarp Bridge was finished in 1930.Langård & Ruud: 120
The line was originally named the Smaalenene Line (), with the spelling changing to Smålenene () in 1921. During this period it was also commonly known as the South Line (), although this was never official. As the line was named for the county, it changed its name after the county changed its name from Smålenene to Østfold.
Parliament approved double track from Oslo to Ljan in 1916. Construction took its time and opened in two stages, from Bekkelaget to Ljan on 1 June 1924 and from Oslo Ø to Bekkelaget on 15 May 1929.Langård & Ruud: 113 South of Ljan the line crossed the Ljan Viaduct, which could not be upgraded to the new standards. A new double-tracked line had to be built around,Langård & Ruud: 117 which opened on 15 February 1925.Bjerke & Holom: 41 By the 1930s the railway was meeting increased competition from buses and trucks. Although slower, they offered more pick-up locations than the train. NSB therefore decided that the Østfold Line, and especially the section closest to Oslo, needed to receive increased capacity, electric traction and more stations.Langård & Ruud: 121 Double tracking continued southwards, opening to Kolbotn on 15 December 1936 and to Ski on 14 May 1939.Bjerke & Holom: 37 Meanwhile, NSB introduced gasoline railcars which stopped at the new flag stops.Langård & Ruud: 127