For the Ofotbanen, which connected the ore mines in Kiruna with the Norwegian port in Narvik, SLM in Switzerland developed the type 19a freight locomotives. These were 2-8-0 two-cylinder compound machines, which were the SLM's most powerful machines to date. To accommodate a wide firebox, the boiler was mounted high. After testing on the Gotthard, the six were delivered to Norway. In 1909 and 1910 three more were built in Norway by Hamar Jernstøberi.

In 1911, two more were built at Hamar, which now were superheated two-cylinder simples. They were designated Type 28a and initially remained two in number. When the Ofotbanen was electrified in 1922, the steam locomotives were relocated to other regions. It was only between 1939 and 1945 that the six remaining members of type 19a were also superheated and simpled and designated type 28b. They were withdrawn between 1955 and 1960.