GNR Class O1

This article is about a class of 2-8-0 steam locomotives of the Great Northern Railway (United Kingdom) introduced in 1913. For the class of 2-8-2 steam locomotives of the Great Northern Railway (United States) introduced in 1911, see Great Northern O-1.

The Great Northern Railway (GNR) Class O1 was a class of two-cylinder 2-8-0 steam locomotive designed by Nigel Gresley for heavy freight work and built by the GNR between 1913 and 1919.

GNR O1 class LNER O1 (later O3) Class
No. 3491 at Immingham Locomotive Depot 1947
Type and origin Power type Steam Designer Nigel Gresley Builder Doncaster Works (5) North British Locomotive Co. (15) Build date 1913–1919 Total produced 20
Specifications Configuration: ​  • Whyte 2-8-0  • UIC 1′D h2 Gauge 4 ft 8+1⁄2 in (1,435 mm) Leading dia. 3 ft 2 in (965 mm) Coupled dia. 4 ft 8 in (1,422 mm) Length 60 ft 11.5 in (18.580 m) Loco weight 76.2–78.65 long tons (77.42–79.91 t) Fuel type Coal Firebox: ​  • Grate area 27 sq ft (2.5 m2) Boiler: ​  • Diameter 5 ft 6 in (1,680 mm) Boiler pressure 180 lbf/in2 (1.24 MPa) Heating surface: ​  • Firebox 162 sq ft (15.1 m2)  • Total surface 2,084 sq ft (193.6 m2) Superheater: ​  • Type 24  • Heating area 570 sq ft (53 m2) Cylinders Two, outside Cylinder size 21 in × 28 in (533 mm × 711 mm) Valve gear Walschaerts Valve type 10-inch (254 mm) piston valves
Performance figures Tractive effort 33,735 lbf (150.06 kN)
Career Operators Great Northern Railway (Great Britain) London and North Eastern Railway British Railways Power class 8F Nicknames Tangos Axle load class Route availability 6 Withdrawn 1947–1952 Disposition All scrapped

History

Gresley designed the O1 2-8-0 for the heavy coal trains on the mainline from Grantham to London, ordering five examples 1913, which were completed at Doncaster in 1914. A further fifteen were ordered in January 1916, but due to the First World War delays were incurred and construction was transferred to the North British Locomotive Company, who delivered the first ten in April 1918, followed by a further five in October and November 1919.

Table of orders and numbers

Year	Order	Manufacturer	Serial number	Quantity	GNR Nos.	LNER Nos.	LNER 1944 Nos.	Notes
1913–14	EO 274	Doncaster Works	1411–1413, 1415, 1418	5	456–460	3456–3460	3475–3479
1919		North British Locomotive Co. (Hyde Park Works)	22060–22069	10	462–471	3462–3471	3480–3489
1919		North British Locomotive Co. (Atlas Works)	22099–22103	5	472–476	3472–3476	3490–3494

The class was re-designated O3 by the London and North Eastern Railway in 1944 to release the O1 classification for use with the LNER Thompson Class O1 introduced during the Second World War.

British Railways

Seventeen examples survived into British Railways ownership in 1948, but all had been withdrawn by 1952 and scrapped after World War 2 .

Table of withdrawals

Year	Quantity in service at start of year	Quantity withdrawn	Locomotive numbers	Notes
1947	20	3	3487, 3490, 3492
1948	17	2	3489/94
1949	15	0	–
1950	15	1	63491
1951	14	10	63475/77–81/83/85–86/93
1952	4	4	63476/82/84/88