four to eight minutes less to the city center, while the tramway would have six to eight departures per hour. The second and final stage of the Ring Line opened on 20 August 2006. Oslo Sporveier was in dire need for more rolling stock and had insufficient to operate along the new line. Because the Ring required that the destination sign be changed mid-way, and this feature was only possible on the T1300 units and were therefore attractive. Oslo Sporveier officially announced the move through deeming the Kolsås Line unsafe for use. A new, temporary station was built at Husebybakken, which became the terminus and opened the same day as the Ring. Services ran a loop around the Ring Line as Line 6 and 4 and continued to Bergkrystallen, using nine T1300 trains. Within a year a few of the departures were being carried out using the new MX3000 trains. With the line closing in Bærum there came a series of protests. A main political concern was the increased traffic and congestion on the highways. The tramway continued to run to Jar, and therefore an extension of this service along the Kolsås Line was called for. After small investments were made the tram to Jar was extended to Bekkestua on 20 August 2007. The unidirectional SL79 trams had to run to Avløs to turn around, although they did not operate revenue services on the last leg, while SL95 trams turned at Bekkestua. The last day with a tram service was 15 February, after which the tram service was cut at Lilleaker. The first upgrades were performed between Åsjordet and Montebello, including the last part of the line from Montebello to Sørbyhaugen. Husebybakken continued as Line 6's terminus until 31 May 2008, after which it was demolished. The first three upgraded stations, Montebello, Ullernåsen and Åsjordet, were put back into the service of Line 6 from 18 August. The upgrades were similar to those to the Røa Line in 1995, including installation of third rail, straight platforms long enough for six-car trains, a new signaling system as well as all-new permanent way and stations. From 22 June 2009 only MX3000 trains were used on the line, and from 11 April 2010 some of the departures started running with six-car trains. Meanwhile, it became evident for the county that they had severely underestimated the conversion costs, which by 2009 were estimated at