In 1937, the first Class B trams were delivered to Oslo Sporveier, and these put into service on the Bærum–Østensjø Line after the serial delivery started in 1939.
Gullfisk |
The first operation on the Lambertseter Line with the SM53-trams was on 10 April 1957, after technical trials had been conducted with the Gullfisk-trams.