was presented in 1991 by Oslo Sporveier, where daily ridership was estimated to be 54,000 passengers. The plans included a possibility for the high-speed Gardermoen Line, that would be built to Oslo Airport, Gardermoen, to have a stop at Storo. This was later discarded when it was instead chosen to be built via Lillestrøm. There were also ideas to run trains from the Hoved Line from Lillestrøm to Grefsen Station via the Alnabru–Grefsen Line, located adjacent to Storo, that would allow the central parts of Groruddalen to connect with the Ring Line and Nordre Aker. When the operating company ordered new T2000 trains for the Holmenkoll Line, the design allowed future versions to have dual current systems, to handle both the 750 volts on the metro network (from a third rail and overhead wire), and the system of the main railways. This would allow the Ring Line to share the physical track with the Gjøvik Line on the section from Storo to Sinsen. The new T2ds were seen as a preparation for the Ring Line, and were optimised for higher speeds than the old stock, being capable of operating at . At the same time, the Sognsvann Line was being upgraded to full metro standard, like the eastern part of the metro had, and would lose the overhead wires and get longer platforms. In 1992, the tram division of Oslo Sporveier launched an alternative Ring Line that would have been built as a light rail, using in part the existing tramway. In the west, it would follow the Sinsen Line via Sinsen to Storo. A new line would have to be built from Storo to Tåsen. The line would then use the existing Sognsvann Line to Majorstuen, where it would connect to the tramway and follow the Frogner Line into the city, via a new Vika Line through Aker Brygge. This alternative would cost NOK 61 million to build, compared to NOK 470 million estimated for the rapid transit solution. Named the Light Rail Ring (), it would have 38 stops instead of 16 stops, and a travel time of 34 minutes instead of 22 minutes. Annual operating costs for the light rail solution would be NOK 57.5 million, compared to 43.9 million for the rapid transit solution. Between 1994 and 1998, there was local political debate about how Rikshospitalet, that was moving to Gaustad, should be served by public