GNR Class O2

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GNR Class O2
Doncaster station geograph-2463320-by-Ben-Brooksbank.jpg
O2/3 2-8-0 No. 3963 at Doncaster 1947
Type and origin
Power typeSteam
DesignerNigel Gresley
Build date1918–1943
Total produced67
 • Whyte2-8-0
 • UIC1'Dh3
Gauge4 ft 8 12 in (1,435 mm)
Leading dia.2 ft 8 in (1 m)
Coupled dia.4 ft 8 in (1 m)
Length63 ft 3 in (19.28 m)
Width8 ft 9 in (2.67 m)
Height12 ft 11.25 in (3.9434 m)
Loco weight74.1–78.65 long tons (75.29–79.91 t)
Tender weight43.1–52 long tons (43.8–52.8 t)
Fuel typeCoal
 • Firegrate area
27.5 sq ft (2.55 m2)
 • Diameter5 ft 4.75 in (1,644.6 mm) or 5 ft 6 in (1,680 mm)
Boiler pressure180 lbf/in2 (1.24 MPa)
Heating surface2,032 sq ft (188.8 m2)
 • Heating area430.5 sq ft (39.99 m2)
Cylinder size18 12 in × 26 in (470 mm × 660 mm)
Valve gearGresley conjugated
Valve type8-inch (203 mm) piston valves
Performance figures
Tractive effort36,740 lbf (163.4 kN)
Power classBR: 8F
DispositionAll scrapped

The Great Northern Railway (GNR) Class O2 was a class of three-cylinder 2-8-0 steam locomotives designed by Nigel Gresley for freight work and built by the GNR from 1921. Further examples were built by the London and North Eastern Railway (LNER) from 1924.


The LNER created four subclasses: [1]

  • O2/1, Introduced 1921. Development of experimental Gresley GNR 3-cylinder locomotive (LNER 3921). Subsequently rebuilt with side-window cab and reduced boiler mountings.
  • O2/2, Introduced 1924. Development of O2/1 with detail differences.
  • O2/3, Introduced 1932. Development of O2/2 with side-window cab and reduced boiler mountings.
  • O2/4, Introduced 1943. Rebuilt with 100A (B1 type) boiler and smokebox extended backwards.


The first models of this class were designed and built under GNR ownership, the first locomotive, 461, was built in May 1918. A batch of 10 further O2s was built by the North British Locomotive Co. in 1921.


Immediately after Grouping (1923), fifteen more O2s were built.

16 more were delivered in 1932/33. Wartime requirements led to the construction of 25 in 1942/43 in three batches.

British Railways[edit]

All 67 locomotives passed to British Railways (BR) in 1948 and were given BR Numbers 63921-63987, but 63921 (which was the prototype 461, LNER 3921) was quickly scrapped. They served all across the former LNER from Stratford through East Anglia into the East Midlands, primarily hauling coal and iron ore trains. By winter 1955/56, they had all gravitated to Doncaster (36A - 35 locomotives), Grantham (35B - 14 locomotives) and Retford (36E - 17 locomotives). By winter 1962, they were down to 52 locomotives still in much the same locations, the following having been scrapped: 63929/34/44/47/50-55/57-59/70.

By the end of 1963 they were all gone, and none was preserved.


O2/2 63942 at Doncaster 1961
O2/4 No. 63966 with side-window cab, band 100A boiler at Retford Locomotive Depot 1962


  1. ^ Ian Allan ABC of British Railways Locomotives, summer 1961 edition, part 4, pp 37–38
  • British Railways Locomotives Combined Volume Winter 1955/56, part 4, p. 32, and the locoshed section, p. 71.
  • British Railways Locomotives Combined Volume 11/62, p. 144
  • Boddy, M. G.; Brown, W. A.; Neve, E.; Yeadon, W. B. (November 1983). Fry, E. V. (ed.). Locomotives of the L.N.E.R., Part 6B: Tender Engines—Classes O1 to P2. Kenilworth: RCTS. ISBN 0-901115-54-1.

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