Class K1/K2

The Great Northern Railway Class H2 and H3 (classified K1 and K2 by the LNER) was a class of 2-6-0 steam locomotive designed by Sir Nigel Gresley for mixed-traffic work.

The class was designed as a locomotive which could haul heavier goods trains at speeds of up to 40 mph. After formation of the London and North Eastern Railway, the type became known as class K1, and the later class K2 was adopted as an LNER standard design. They got the nickname “Ragtimers” because of their lively nature when running at speed and their use of Walschaerts valve gear which was uncommon on the GNR at the time.

The ten class K1s were built at the GNR’s Doncaster Works in 1912–1913, to the design of Nigel Gresley. Five batches of class K2s, totally 65 locomotives, were built at Doncaster, the North British Locomotive Company, and Kitson & Company between 1914 and 1921. These were the first design to incorporate Gresley’s patented double swing link pony truck design.

A larger diameter boiler was designed in July 1913 for fitting to further 2-6-0s. These were fitted to the next batch of 2-6-0s which were ordered in August 1913 to become GNR class H3 (LNER class K2). The firebox was 6in longer although the throatplate sloped backwards resulting in the same length at the base. The larger boiler also allowed the fitting of a Robinson superheater. The class K2 also had longer frames and the pony truck was 4in further forward of the leading drive axle.

They were excellent mixed-traffic locomotives, but began to be displaced by the larger and more powerful class K3s. They were moved to former the Great Eastern and North British lines to supplement existing locomotives. Twenty class K2s were fitted with Westinghouse pumps so they could pull passenger trains from Liverpool Street on the Colchester and Cambridge lines.

No. 4635 was rebuilt from class K1 to class K2 in 1920. No. 4631 was rebuilt in 1921. No further K1s were rebuilt until 1931, when a shortage of K1 boilers necessitated rebuilds. The remaining eight were rebuilt between 1931 and 1937, making the K1 class extinct. From 1938, the classification of class K2/1 was used for the rebuilt class K1s, and class K2/2 for the original class K2s.

The class K1s were numbered No. 1630–1639 by the GNR, and became LNER No. 4630-4639. The class K2s were numbered No. 1640–1704 by the GNR, and became LNER No. 4640-4704. In the LNER’s 1946 renumbering programme, the class K2s were renumbered No. 1720–1794, and they later became British Railways No. 61720–61794.

Other than the rebuilding of the class K1s as class K2s, the only significant changes made by the LNER were to all these GNR locomotives to run on the restrictive loading gauges of the Great Eastern (GER) and North British (NBR) lines. The class K1s were quickly fitted with shorter chimneys in 1923 enabling them to work on GER lines. These started to appear on GER and NBR lines as they were displaced by new class K3s from 1924. The modifications consisted of a shorter chimney and dome cover, lowering of the cab roof, moving the whistles, and replacement of Ramsbottom safety valves with Ross pop valves. From 1924-25, the class K2s would become regular workers on the West Highland line and in East Anglia.

Between 1927 and 1928, twenty class K2s had Westinghouse pumps fitted so that they could work passenger services from Liverpool Street on the Colchester and Cambridge lines. The class K2 cabs were not very popular with the Scottish crews, so between 1932 and 1935, the Scottish class K2s had side window cabs fitted. When further class K2s were transferred to Scotland, they would similarly have their cabs rebuilt.

None of the class K1s were named. However, some of the class K2s based in Scotland received names in 1933–34.

LNER Number	BR Number	Name
4674	61764	Loch Arkaig
4682	61772	Loch Lochy
4684	61774	Loch Garry
4685	61775	Loch Treig
4691	61781	Loch Morar
4692	61782	Loch Eil
4693	61783	Loch Sheil
4697	61787	Loch Quoich
4698	61788	Loch Rannoch
4699	61789	Loch Laidon
4700	61790	Loch Lomond
4701	61791	Loch Laggan
4704	61794	Loch Oich

All 75 K2s survived into British Railways ownership. At this point, 31 were allocated to the western section of the Southern Area, 23 to the Eastern Area, and 21 to the Scottish Area. The first class K2 was withdrawn in 1955. Four were converted for use as stationary boilers, but the last of these was withdrawn in 1961. The class K2s finally became extinct in 1962 with the withdrawal of No. 61756. None were preserved.

To find out more about the Gresley class K1s and class K2s, visit LNER.info or wikipedia. Volume 6A of the RCTS ‘Locomotives of the LNER’ and volume 18 of ‘Yeadon’s Register of LNER Locomotives’ covers the classes in detail.