It runs from the classification yard at Loenga(Norway) to Alnabru Freight Terminal, typically serving twenty trains per day.

It is also used by freight trains from the Sørlandet Line, which run via the Oslo Tunnel and cross over at Bryn Station.

In order to bypass Brynsbakken, the Norwegian National Rail Administration has proposed building a tunnel from further south on the Østfold Line, named the Bryn Diagonal.

The 7.33-kilometer (4.55 mi) Loenga–Alnabru Line connects the classification yard at Loenga with Alnabru Freight Terminal, both in Oslo.

The line has single track and standard gauge and is electrified at 15 kV  16.7 Hz AC.

At Etterstad there is a switch which allows trains to pass to and from the Gardermoen Line, just before the latter enters the Romerike Tunnel.

At Bryn Station, 3.89 kilometers (2.42 mi) from Loenga, there is a switch allowing trains access from the Trunk Line.

Parliament decided in 1897 that the Gjøvik Line's freight trains would be handled at Loenga.

[3] Oslo East Station was soon too small and there was need for additional sites for classification and cargo handling.

The need to keep the gradient at bay meant that the tracks were placed at a lower elevation than the Trunk Line, with the two not reaching the same height until Bryn Station.

[8] The Norwegian State Railways bought the farm Nordre Alna in 1918, allowing for a further development of the station.

[1] A series of road constructions in the Bryn area caused the Loenga–Alnabru Line to receive new structures.

A set of sixteen freight cars began rolling out of control during shunting at Alnabru.

[12] These currently only consist of about nine weekly services which haul jet fuel to Oslo Airport, Gardermoen.

[14] Travel time is about 12 minutes from Loenga to Alnabru, with an average speed of about 40 kilometers per hour (25 mph).

Lacking any passing loops, the line has a theoretical capacity for two trains per direction per hour.

[16] Development of the corridor would allow for direct intermodal train services to destinations in Central Europe.

Brynsbakken has therefore been identified as a bottleneck in transport from the Sørlandet Line, Sweden and the Continent to Alnabru.

[18] Increased capacity southwards will allow for more freight trains towards Gothenburg, Denmark and the continent.

Although this would cut some costs, it would still delay each train by about 25 minutes and requires additional tracks at both Loenga and Alnabru.

The complexity, cost and maintenance of an intersection was regarded as not worthwhile for the limited amount of traffic.