The bridges and viaducts were all designed by Axel Jacob Petersson. The Western Line from Oslo to Halden was taken into revenue service on 2 January 1879. Construction of the Eastern Line was delayed and was opened in stages. The section from Ski to Spydeberg taken into use on 1 February 1882. Next followed the line to Slitu on 17 July. Ordinary operations commenced on 24 November. From the 1890s there were two morning trains which ran from Mysen to Oslo. The station was therefore equipped with a roundhouse for two locomotives. A military battery was established at Langnes Bridge in 1899. Askim Station became a hub for three branch lines. The Kykkelsrud Line was built in 1899to allow access to the pulp mill Glommens Træslliperi. It was extended to Kykkelsrud between 1914 and 1918 in conjunction with the construction of Kykkelsrud Power Station. The Vamma Line was completed in 1909 and later extended. It was used to construct Vamma Power Station. The first was the Solbergfoss Line, which opened in 1918 to allow the construction of Solbergfoss Power Station. The line proved popular and continued with passenger train operations until 4 January 1965. Hafslund built the Hafslund Line from the Eastern Line to their main plant. Built between 1897 and 1899, it remained in use until 1974. The same years there was also a branch line from Rakkestad Station to Rakkestad Tegelverk. Railcars were introduced on the Eastern Line in 1928. This was a move to make the train more competitive against buses and trucks, which had better surface coverage than the train. The railcars would initially stop at request, normally at level crossings. This was formalized in 1932, when 38 new stations were official established. A large number of these were closed in 1947. The Østfold Line was electrified in 1940, after which all trains on the Eastern Line stopped at Ski for transshipment. Throughout the 1950s there grew up more urban areas around some of the largest stations. The most prominent were Askim, Mysen and Rakkestad, which all received a prominent town center and grain silos. The Eastern Line was finished electrified on 4 December 1958. The allowed for faster and direct services to the capital. The electrification cost 17 million kroner. Services were predominantly offered with NSB Class 68 multiple units.