LNER Thompson Class B1

Type and origin
Type and origin
Power type	Steam
Designer	Edward Thompson
Builder	Darlington Works (60); Gorton Works (10); North British Locomotive Co. (290); Vulcan Foundry (50)
Build date	1942–1952
Total produced	410

LNER Thompson Class B1
LNER Thompson Class B1
	61059 at Norwich Thorpe, January 1958.
Power type
Type and origin
Power type	Steam
Designer	Edward Thompson
Builder	Darlington Works (60); Gorton Works (10); North British Locomotive Co. (290); Vulcan Foundry (50)
Build date	1942–1952
Total produced	410
Configuration:;
Specifications
Configuration:;
• Whyte	4-6-0
• UIC	2′C h2
Gauge	4 ft 8+1⁄2 in (1,435 mm) standard gauge
Leading dia.	3 ft 2 in (0.965 m)
Driver dia.	6 ft 2 in (1.880 m)
Axle load	17 long tons 15 cwt (39,800 lb or 18 t)
Loco weight	71 long tons 3 cwt (159,400 lb or 72.3 t)
Fuel type	Coal
Boiler	LNER diagram 100A
Boiler pressure	225 psi (1.55 MPa)
Cylinders	Two, outside
Cylinder size	20 in × 26 in (508 mm × 660 mm)
Valve gear	Walschaerts
Valve type	10-inch (254 mm) piston valves
Tractive effort
Performance figures
Tractive effort	26,878 lbf (119.56 kN)
Operators
Career
Operators	LNER » BR
Class	LNER: B1
Power class	BR: 5MT
Numbers	LNER:1000-1409, BR : 61000-61409
Nicknames	Bongos, Antelopes
Axle load class	Route Availability 5
Locale	Eastern Region; North Eastern Region; Scottish Region;
Withdrawn	1961–1967
Preserved	(6)1264, 61306
Disposition	Two preserved, remainder scrapped

The London and North Eastern Railway (LNER) Thompson Class B1 is a class of steam locomotive designed by Edward Thompson for medium mixed traffic work.