Four tank locomotives were ordered for the opening of the Dunderlandsbane by the British mining company DIOC, of which the two larger ones came from Kerr, Stuart & Co. They had the wheel arrangement 2-6-2T and were adapted to the climate in Norway with a closed cab. When the Dunderlandsbane was integrated into the NSB network in 1947, these locomotives were also taken over. They now became the Type 54a, the last of which was in service until 1957.