The reference for locomotives and railcars


Page views since 2023-01-26: 261063
Great Northern (UK) class O2
London & North Eastern class O2
Great Britain | 1918 | 67 produced
No. 477, the first production engine
No. 477, the first production engine
Locomotive Magazine, June 1921

As a development of the O1, the O2 was created, which initially differed almost only in the number and arrangement of the cylinders. Instead of the previous two cylinders, three smaller ones were used to improve power transmission and smooth running. On these locomotives, Gresley used his special valve motion for the first time, in which the inner cylinder was controlled by levers from the valve gear of the outer cylinders. As a result, no additional motion was needed within the frame that would difficult to access for maintenance. The dimensions of the boiler were left unchanged compared to the O1, but the starting tractive effort was increased by around nine percent thanks to the third cylinder.

British Railways No. 63942 with original GNR cab and BR logo in 1961
British Railways No. 63942 with original GNR cab and BR logo in 1961
Ben Brooksbank / LNER 2-8-0 at Doncaster Locomotive Depot fresh from repair at the Works

In 1918 only one prototype could be completed, another ten units with slightly modified controls were ordered in 1919 and delivered in 1921. The production engines got cylinders half an inch larger and an increase in boiler pressure from 170 to 180 psi. After the grouping in 1923, the LNER ordered another 15, which, given the smaller LNER standard loading gauge, got a flatter cab with side windows, a lower chimney and a repositioned whistle. Many of the earlier engines were also converted in this form in 1939 in order to be able to use them in the entire LNER network. Another 16 were delivered in 1932 and 1933 and the last 25 in 1942 and 1943.

Schematical drawing with dimensions
Schematical drawing with dimensions
Locomotive Magazine, June 1921

At first the O2, like the O1 before it, mainly delivered coal to London. During the war, many engines also had to transport other cargo on behalf of the military. After the end of the war, most of them pulled coal and ore trains again, since they belonged to the group of “mineral engines” and were well suited for this. All 67 locomotives came to the British Railways in 1948 and only the prototype was quickly retired due to its different valve gear. It was only in 1960 that the other engines were also retired, which was completed in 1963. Like most British goods locomotives, the O2 were all scrapped at the end of their service life.

ManufacturerDoncaster, North British
Axle config2-8-0 (Consolidation) 
Gauge4 ft 8 1/2 in (Standard gauge)
Dimensions and Weights
Length61 ft 4 3/4 in
Wheelbase27 ft 2 in
Fixed wheelbase18 ft 6 in
Total wheelbase52 ft 2 1/4 in
Service weight171,136 lbs169,792 lbs
Adhesive weight149,184 lbs150,864 lbs
Total weight267,680 lbs266,336 lbs
Axle load38,304 lbs39,424 lbs
Water capacity5,044 us gal
Fuel capacity16,016 lbs (coal)
Power sourcesteam
Estimated power1,150 hp (858 kW)1,175 hp (876 kW)
Optimal speed22 mph21 mph
Starting effort32,605 lbf36,468 lbf
Power Plant
Driver diameter56 in
Boiler pressure170 psi180 psi
Expansion typesimple
Cylindersthree, 18 x 26 inthree, 18 1/2 x 26 in
Grate area27.5 sq ft
Firebox area163.5 sq ft
Tube heating area1,926.5 sq ft1,868.5 sq ft
Evaporative heating area2,090 sq ft2,032 sq ft
Superheater area431 sq ft
Total heating area2,521 sq ft2,463 sq ft
Calculated Values
steam locomotive
Herbert Nigel Gresley
last changed: 01/2022

We use cookies to save the following settings:

  • selected navigation structure
  • selected language
  • preferred units
  • spelling of railway company names

If you refuse the use of cookies, the settings will only be retained for the current session and will be reset to the default values the next time you visit the site.

Display of units

Here you can set the desired unit system for the technical data.

  • Metric: Lengths in meters, weights in tonnes, and volumes in cubic meters
  • Imperial (UK): Lengths in feet/inches, weights in long tons and volumes in imperial gallons
  • Imperial (US): Lengths in feet/inches, weights in pounds, and volumes in US gallons
  • Individual: Depends on the country of origin of each locomotive
Operator names

Here you can set the display of railway company names.

  • Short: Abbreviation or short form of the name
  • Standard: commonly used name, partially translated to English
  • Complete: full name in local language