The line is served by route 17 and 18 by Oslo Sporvognsdrift using SL95 trams, while the tracks are owned by Kollektivtransportproduksjon.

[2] In 1924, the line, along with the rest of the street tram network, was taken over by the municipal Oslo Sporveier.

On 1 August 1925, the line was extended to Ullevål Hageby (later renamed John Colletts plass).

[3] In 1988, the Norwegian Parliament decided to start the process of moving Rikshospitalet, the National Hospital, from Pilestredet to Gaustad.

[4] Following the completion of the architectural plans in 1991, the city planner launched the concept for transport to the new hospital.

[5] Specific plans for the extension were launched in April 1992, and were estimated to cost 100 million kr.

[6] The regulation plan for the hospital, and the go-ahead for the construction of the line, was passed by the city council on 4 May 1994.

[7] In April 1996, a disagreement between the municipality and the Ministry of Transport arose concerning who should be paying for the extension.

The politicians signalled that they instead wanted to look at possibilities of serving the hospital with rapid transit and bus.

While the line was not initially part of the package, it served as a prelude in combining state and municipal grants to public transport investments.

[13] The 1.6 kilometres (0.99 mi) extension[14] was ready for trial runs on 25 May 1999, when a new SL95 tram made a tested.

The line was the crime scene of a murder on 3 August 2004, when a mentally deranged man went on a stabbing spree on board a tram at Bislett, injuring five and killing one.

[17] From downtown, the line runs in a generally northern direction, gradually turning northwestwards, moving along Thereses gate and Sognsveien to John Colletts plass, then through Niels Henrik Abels vei, on the north side of the University of Oslo campus, before ending at Rikshospitalet.

The leg between John Colletts plass and Rikshospitalet is formally called the Gaustad Line (Gaustadlinjen).