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.

The first four examples of the type 18a were built in 1900 by Hartmann in Chemnitz for the Norwegian Northern Railway. Another four followed the next year, which were also to be used on other routes, and in 1903 two more followed, which were manufactured in Norway by the Hamar iron foundry. These were saturated locomotives with a 4-6-0 wheel arrangement and two-cylinder compound engine. The axle load of the coupled axles was almost twelve tonnes each and the top speed was 60 km/h. In 1907, six more locomotives followed, which were a bit heavier and were therefore designated as Type 18b.

A total of 19 examples of the Type 18c were produced between 1910 and 1919 as a result of a major revision. They were designed using superheated steam technology and had a simple two-cylinder engine without compound action. At the same time, the boiler pressure was reduced from 13 to 12 bars and the speed could be increased to 65 km/h. Almost all of the type 18a and 18b locomotives were subsequently converted, some of which did not happen until 1948. From this point on, it wasn't long before the locomotives were relegated to lower roles and retired in the 1960s. The 18c with the number 255 from 1913 is still operational today after being refurbished between 1980 and 1992.

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.

The Bergensbane, or Bergen Railway, connects Oslo with Bergen and, despite a large number of tunnels, has challenging gradients, so that the express trains at the beginning of the century had to rely on pilot locomotives. For this reason, the NSB launched an invitation to tender for a powerful express train locomotive that should be able to cover this route without double-heading. The route has a constant gradient of 2 to 2.1 percent over a length of 70 km, which culminates at an altitude of 1301.7 meters at Lake Taugevatn and has curve radii of 180 meters. However, the tracks required a maximum axle load of twelve tonnes, while a locomotive with four cylinders was specified to further reduce the loads on the rails.

The winner of this tender was the locomotive later designated as the type 26, which was designed by the Schweizerische Lokomotivfabrik in Winterthur. The required power was achieved with four coupled axles and a leading bogie. Thanks to the boiler being placed very high, it was possible to accommodate a wide firebox without a trailing axle. The locomotives were able to haul trains weighing 200 tonnes at 35 km/h on the aforementioned incline.

The three locomotives delivered by SLM in 1910 were designated type 26a and were, however, somewhat lighter than expected. In order to be able to fully utilize the available axle load, two more units were ordered from Thune in Oslo, which were a bit heavier and were designated type 26b. The largest sub-series with 17 units was the type 26c, which was designed as a compound machine due to the high steam consumption of the four cylinders. It was supplied by several manufacturers between 1919 and 1924.

Schematic drawing

Locomotive Magazine, August 1917

As early as 1915, the type 26 locomotives were withdrawn from the Bergen Railway, as the latter had been converted for a higher axle load and the heavier type 31 locomotives were now being used there. Thanks to the small coupling wheels, they were suitable for all types of trains and were therefore used in different parts of Norway in different roles. Rebuilds took the form of an oil-fired engine in the 1950s and the fitting of an engine with a larger boiler in 1961. The locos survived until 1969, when the last year of steam service in Norway had struck. Two pieces were kept in reserve in 1970 in case diesel locomotives failed.

When the Bergen Railway was converted for higher axle loads, more powerful locomotives than the type 26 could be used there. This resulted in the type 31 with the same axle arrangement, but with a higher weight and boiler pressure. In 1915, two locomotives were initially built which, like the types 26a and 26b, had a four-cylinder engine with simple expansion.

Locomotive Magazine, August 1917

The high tractive power that could be achieved for a short period of time by this engine was used to push snow blowers on the Bergen Railway. In 1920, two more identical locomotives followed for the same purpose, which were also supplied by Thunes from Oslo and were designated together with the first two as type 31a.

Sectional drawing

Locomotive Magazine, August 1917

As with its predecessor, the majority of locomotives were built with compound engines in order to be able to maintain a similarly high tractive effort over a longer period of time. These locomotives, which were designated as Type 31b, were supplied by various manufacturers between 1923 and 1926 and took over the tasks of the type 26. They thus pulled different train types on the Bergen Railway until the Nohab diesel locomotives of the Di 3 type were introduced there in 1957 and 1958.

They were now distributed to other locations where there was no electrification or where diesel locomotives were not yet available. They spent their final years on branch lines that could withstand the weight of these locos. Only the four type 31a locomotives remained in service until the end of their lives in their traditional role as pusher locomotives for the snow blowers and were not put out of service until 1970.

The NSB had the largest and most powerful steam locomotives ever used in Norway built to operate the increasingly heavier express trains on the steeply graded Dovre Railway. They became known by the nickname “Dovregubben”. They were built in the 2-8-4 design in order to achieve a high tractive force in addition to be able to accommodate a large firebox, with which a large steam production could be maintained on long inclines. Since high speeds could not be run on the route and traction was more important, the driving wheels were designed with a diameter of just 1,530 mm and a top speed of 90 km/h was enough. Since the total length was also limited due to the existing turntables, the smaller driving wheels also made it possible to accommodate the four driving axles. These were necessary in order to be able to maintain the maximum axle load of 15.5 tonnes on the mountain routes. The engine was designed with four cylinders and compound action.

The first two machines, later designated type 49a, were delivered by Hamar and Thune in June and September 1935. Despite the small wheels, one reached 115 km/h at a press tour. The pronounced lightweight construction of the entire locomotive led to problems in some places, which was improved by adapting some parts. The one-off type 49b, which was also built in Norway, followed the next year. The bogie had an engageable booster with drive on both axles in order to provide additional tractive power for starting and on steep inclines.

Two of the Type 49c were delivered by Krupp in 1940 and two by Thunes in 1941. These had no booster and were similar to the 49a, but with some detail improvements. This included making the cylinders smaller in order to save weight and to strengthen the axles at the same time. Seven more were destroyed in a bombing raid on the Krupp factory in World War II, four others were never completed in Norway and were used as spare parts donors.

Sectional drawing of type 49c

Die Lokomotive, September 1941

Due to the four cylinders, the locomotives were very demanding in terms of maintenance, but were able to fully convince in terms of their performance and economy. The economy was even certified in Germany by the Grunewald Locomotive Testing facility during tests with one of the locomotives built by Krupp. When the NSB introduced the Di 3 diesel locomotives, they were initially used together with the type 49. It quickly became apparent that the steam locomotives could maintain their speed much better on long inclines than the diesel locomotives with 1,900 hp. However, since the latter were much easier to maintain, all type 49 were retired by 1958.