The line originally ran 90 kilometers (56 mi) north from Arendal to Treungen and the lake Nisser, but the upper-most part has been removed.

Although electrified at 15 kV  16.7 Hz AC,[1] it lacks centralized traffic control[2] and Global System for Mobile Communications – Railway.

[6] Planning of the line started in 1874, when Aust-Agder County Municipality (then Nedenes) established a railway committee.

In Nordenes, it was proposed that both Arendal and Grimstad would have a branch line, which would connect somewhere north of towns, and continue northwards into the interior.

The proposed line would have branches to Skien, Kragerø, Arendal, Åmli, Risør, Grimtad, Tvedestrand and Notodden.

[8] The plans were based on a station on the southern shore Langesævannet in Arendal, with a branch which would continue to the port at Ormviken.

The line passed by parliament would run from Arendal via Harebakken, Blaakestad, Lyngraat Grube and Hersel to Bøylestad to Åmli.

The plans, which were not voted over, involved the line continuing northwards to the country border to Telemark (then Bratsberg), where it would branch in two and run to Drangsvannet and Tveitsund.

[9] The parliamentary decision required that 20 percent of the 4.2 million Norwegian krone (NOK) cost be granted locally.

Sam Eyde was hired to make a new plan, and he proposed filling up Kittelsbukt and placing the station in the town center.

[14] The upper section was to be built as class III, a light standard with a minimum curve radius of 250 meters (820 ft) and level crossings instead of underpasses for public roads.

On 1 July 1907, parliament amended their decision by changing the route slightly at Bøylefoss and Flatenfoss to allow dams to be built.

Particularly the section from Arendal to Rise and from Froland to Simonstad required much leveling, and along the 21 kilometers (13 mi) from Evenstad to Foløya there was no road.

The Vestland Line Railway Committee sent a petition to the ministry on 28 November, stating that construction was going too slow, and that the municipalities had paid the necessary dues years ago.

On 23 December, Lund stated that the 16-kilometer (9.9 mi) long section between Arendal and Froland would be opened the following year.

[19] The first official opening of the line took place on 17 December 1910 by Prime Minister Wollert Konows, when the whole section from Arendal to Åmli was taken into use.

All trains running to Åmli were extended to Treungen, and the line received some new rolling stock,[27] including two Class XXIIId locomotives.

[31] In 1910, construction work started for Bøylefoss Power Station; the railway ran right past and was used for transport of both materials and people.

This resulted in additional halts being created, and for a short while the multiple units would even stop at road crossings.

In addition to dispatching post, he sold newspapers, magazines, lottery tickets and could be hired to perform various smaller tasks while he was in Arendal.

[41] While terminus for the Sørland Line, Arendal experienced a larger increase in traffic, as all transport to the South Coast went through the town.

However, the number of services along the line increased slightly, in part to allow fish to be transported with the express train to Oslo.

[60] NSB proposed that the line be closed in 1966, and in April 1967, the Standing Committee on Transport and Communications had an inspection of the area, particularly looking at roads.

The decision to close the line from 1 October 1967 was made by parliament on 22 June, and included NOK 12 million for new roads.

[61] Parliamentarian Osmund Faremo attempted to reopen the line in April 1968, but this was rejected by Minister Håkon Kyllingmark.

[1] NSB introduced Class 68 trains on the line, which were at the time the oldest electric multiple units used by the company.

[70] Six months later, NSB stated that unless they received addition grants, many smaller services, including the Arendal Line, would have to be terminated.

[72] In 2000, the railway company Timetoget had negotiated an agreement with NSB to take over passenger operations on the Bratsberg Line.

With the introduction of the Class 73, NSB also proposed establishing a direct morning express from Arendal to Oslo without transfer at Nelaug.

NSB had a large shortage of motormen, and chose to close operations on the lines with least traffic to allocate sufficient personnel to areas with higher ridership.