LNER Class W1

Specifications
Specifications
Configuration:;
• Whyte	4-6-4
• UIC	2′C1.1′ h4v; later 2′C1.1′ h3
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 8 in (2.032 m)
Trailing dia.	3 ft 2 in (0.965 m)
Fuel capacity	9 long tons (9.1 t; 10 short tons)
Water cap.	5,000 imp gal (23,000 L; 6,000 US gal)
Firebox:
• Grate area	Original: 35 sq ft (3.3 m2); Rebuilt: 50 sq ft (4.6 m2)
Boiler	Original: Diagram 103; Rebuilt: Diagram 111
Boiler pressure	Original: 450 psi (3.10 MPa); Rebuilt: 250 psi (1.72 MPa)
Cylinders	Original: Four (compound); two high pressure inside; two low pressure outside; Rebuilt: Three (simple)
Cylinder size	Rebuilt: 20 in × 26 in (508 mm × 660 mm)
High-pressure cylinder	Original: 12 in × 26 in (305 mm × 660 mm); bore later reduced to 10 in (254 mm)
Low-pressure cylinder	Original: 20 in × 26 in (508 mm × 660 mm)
Valve gear	Walschaerts (outside only post-rebuild), Gresley Conjugated inside post-rebuild

Type and origin
Type and origin
Power type	Steam
Builder	Darlington Works
Build date	1929
Total produced	1
Rebuilder	Doncaster Works
Rebuild date	1936

LNER Class W1
LNER Class W1
Power type
Type and origin
Power type	Steam
Builder	Darlington Works
Build date	1929
Total produced	1
Rebuilder	Doncaster Works
Rebuild date	1936
Configuration:;
Specifications
Configuration:;
• Whyte	4-6-4
• UIC	2′C1.1′ h4v; later 2′C1.1′ h3
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 8 in (2.032 m)
Trailing dia.	3 ft 2 in (0.965 m)
Fuel capacity	9 long tons (9.1 t; 10 short tons)
Water cap.	5,000 imp gal (23,000 L; 6,000 US gal)
Firebox:
• Grate area	Original: 35 sq ft (3.3 m2); Rebuilt: 50 sq ft (4.6 m2)
Boiler	Original: Diagram 103; Rebuilt: Diagram 111
Boiler pressure	Original: 450 psi (3.10 MPa); Rebuilt: 250 psi (1.72 MPa)
Cylinders	Original: Four (compound); two high pressure inside; two low pressure outside; Rebuilt: Three (simple)
Cylinder size	Rebuilt: 20 in × 26 in (508 mm × 660 mm)
High-pressure cylinder	Original: 12 in × 26 in (305 mm × 660 mm); bore later reduced to 10 in (254 mm)
Low-pressure cylinder	Original: 20 in × 26 in (508 mm × 660 mm)
Valve gear	Walschaerts (outside only post-rebuild), Gresley Conjugated inside post-rebuild
Tractive effort
Performance figures
Tractive effort	Original: 32,000 lbf (142.3 kN); Rebuilt: 41,437 lbf (184.3 kN)
Operators
Career
Operators	LNER » BR
Class	W1
Power class	BR: 8P
Numbers	LNER: 10000; BR: 60700
Nicknames	Hush-Hush
Axle load class	Route Availability: 9
Withdrawn	June 1959
Disposition	Scrapped

The LNER W1 No. 10000 (also known as the Hush-Hush due to its secrecy) was an experimental steam locomotive fitted with a high pressure water-tube boiler. Nigel Gresley was impressed by the results of using high-pressure steam in marine applications and so in 1924 he approached Harold Yarrow of shipyard and boilermakers Yarrow & Company of Glasgow to design a suitable boiler for a railway locomotive, based on Yarrow's design.