4-8-4

With Northern steam locomotives are designated with the wheel arrangement 2'D2 ', ie with a leading bogie, four driving axles and a two-axle trailing travois.

The first locomotive with this wheel has only emerged in 1926 - one month before the first Hudson ( 2'C2 ') - which the Northern one of the youngest axis sequences. Its name from the type of the Northern Pacific Railway, for the first locomotive was built with this wheel. Some railways have the name Northern not, however, so this type occasionally with Confederation (in Canada), Niagara is called (with the New York Central Railroad ), Pocono and other terms.

The first Northern, built by ALCO locomotive No 2600 of the Northern Pacific Railway was designed for the combustion of brown coal with low calorific value, so that a 10.7 m² rust and a correspondingly large firebox was required for the power needed for to a single drive axle was no longer sufficient. The locomotive was successful, and the design was soon copied by other railways. Northern locomotives represented a good compromise between speed and traction and could be used as a universal locomotives both prior express trains as well as not too heavy freight trains.

In North America (Canada, USA and Mexico) total 1126 Northern were built 1926-1950, of which the Canadian National Railway with 203 pieces, most possessed.

The fastest measured on a Northern under controlled conditions speed reached the mapped class J of the Norfolk & Western Railroad. Despite its 1778 mm with not very large driving wheels, the locomotive No. 610 reached in comparison tests with the class T1 of the Pennsylvania Railroad, a speed of 177 km / h Other locomotives such as the class S -1 ( Niagara ) of NYC and the Class of 2900 ATSF even be said to have higher speeds. Exceeded all of these locomotives in daily operation on a regular basis the 100 - mph limit (161 km / h) and were the fastest four -coupled locomotives ever.

In Europe Northern locomotives were rare. The largest number of vehicles, about 250 pieces, ran in Russia, ten in Spain, two in Germany and one in France. However, the two German locomotives of Class 06 had multiple defects, and after the war, a reconstruction of the two individual pieces was not worth it, so they were retired early. The other hand, was very successful, the French 242 A, a 1946 arising under the direction of André Chapelon conversion from a 2'D1 '. With a cylinder capacity of up to 5700 hp, it was the most powerful European steam locomotive, and only the transition to electric and diesel operation prevented the building of further locomotives of this type

The Northern used the longest were from 1953 built 140 locomotives of Class 25 and 25 of the South African Railways NC, of which 90 were equipped with a condensing tender. Quite a few of the locomotives were retired only in the 1990s. The No. 844 of Union Pacific Railroad was continuous from 1944 to today in use in hand, travels, however, since about 1960, only special trains.