Class B and Class E, normally referred to as Gullfisk (Norwegian for "goldfish"), were a class of 46 trams built by Strømmens Værksted and Skabo Jernbanevognfabrikk for Oslo Sporveier and Bærumsbanen of Oslo, Norway, in 1937 and 1939. They were the first aluminium trams to operate on the Oslo Tramway and the first bogie trams to operate on street lines. They had contemporary modern electronic equipment, a streamlined shape, and comfortable accommodation.