same day Ullernåsen was moved midway between its old location and that of Mærradalen. Husebybakken was closed for traffic on 19 June 1961, due to low ridership and close proximity to nearby stations. During the 1960s, the rectifier at Jar was replaced with a more modern one at Øraker and a new garage built at Avløs Depot. Since the 1960s, ridership remained stable at about four million passengers per year. From 1971, Bærumsbanen was liquidated and ownership and all aspects of operation of the line was transferred to Oslo Sporveier. Holmenkolbanen started taking delivery of the T1300 series of combined metro and tram multiple units in 1978. This caused Oslo Sporveier to put HKB 500 units into service on the Kolsås Line. The use of T1300 stock on the Kolsås Line required several upgrades: the platforms height was raised and the power supply was improved with new rectifiers at Ringstabekk and Kolsås. With the second delivery of T1300 stock in 1980 and 1981, the new units were put into service on the Kolsås Line. The T6 series of fifteen units were built with a driver's cab at both ends, so single-car trains could be operated in the evenings. This resulted in Class D being taken out of use in 1982. The conductor was removed from the service from 21 June 1982, when the T1300 entered service. During rush hour, Class C units were still in use and these retained their conductors. Stortinget Station opened on 7 March 1987, allowing Line 14 was extended further into the city center. This section was incompatible with Class C units and these were therefore retired. To meet the required number of trains, six T1000 units were converted to T1300. The Røa Line from Sørbyhaugen to Volvat closed on 18 May 1995, allowing the Røa Line upgraded to metro standard. At the same time, the Lillaker Line tram was extended from Jar to Kolsås. The upgrade involved the line receiving automatic train control with cab signaling, third-rail power supply and longer platforms. Until 20 August, Line 14 only operated between Kolsås and Montebello. After the Røa Line reopened, the third rail had been laid to Montebello, and the trains had to switch power supply and signaling system there. The Kolsås Line was connected with the Lambertseter Line east of the city center from 19 November 1995, taking line number 4 and with operations running through