LNER Class B17

LNER Class B17

B17/6 No. 61642 Kilverstone Hall.

Type and origin Power type Steam Designer Nigel Gresley Builder North British Locomotive Co. (10) Darlington Works (52) R. Stephenson & Co. (11) Serial number NBL: 23803–23812 RS: 4124–4134 Build date 1928–1937 Total produced 73

Specifications Configuration: ​  • Whyte 4-6-0  • UIC 2′C 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) Length 58 ft 4 in (17.78 m) Width 8 ft 11 in (2.72 m) Height 12 ft 11 in (3.94 m) Loco weight 77.25–80.5 long tons (78.49–81.79 t; 86.52–90.16 short tons) Fuel type Coal Boiler pressure B17/1 to B17/5: 180 psi (1.24 MPa) B17/6: 225 psi (1.55 MPa) Heating surface 1,676 sq ft (155.7 m2)  • Firebox 168 sq ft (15.6 m2) Superheater: ​  • Heating area 344 sq ft (32.0 m2) Cylinders Three Cylinder size 17 1⁄2 in × 26 in (444 mm × 660 mm) Valve gear Outside: Walschaerts Inside: Gresley conjugated Valve type 8-inch (203 mm) piston valves

Performance figures Tractive effort B17/1 to B17/5: 25,380 lbf (112.9 kN) B17/6: 28,553 lbf (127.0 kN)

Career Operators LNER » BR Power class BR: B17/1 to B17/5: 5MT; B17/6: 6P5F Axle load class Route Availability 5 Withdrawn 1952–1960 Disposition All original locomotives scrapped, one replica and one new-build under construction

The London and North Eastern Railway (LNER) Class B17, also known as "Sandringham" or "Footballer" class was a class of 4-6-0 steam locomotive designed by Sir Nigel Gresley for hauling passenger services on the Great Eastern Main Line. In total 73 were built.

By 1926, the former GE B12 class locomotives were no longer able to cope with the heaviest express passenger trains on the Great Eastern Main Line between London and Cambridge, Ipswich and Norwich. Yet Gresley was unable to use his larger classes due to severe weight restrictions on the line. The requirement for a lightweight yet powerful 4-6-0 proved to be difficult to achieve.

After several unsuccessful attempts by Doncaster Works to satisfy Gresley's specification, the contract for the detailed design and building of the class was given to the North British Locomotive Company in 1927. They used several features from a batch of A1 Pacifics they had built in 1924. The cab, cylinders, and motion had all been copied directly or slightly modified. Most of the boiler design was taken from the LNER Class K3 2-6-0 and LNER Class O2 2-8-0 designs. Darlington Works provided drawings for the bogies, and Stratford Works designs for the GE-type 3,700-imperial-gallon (17,000 l; 4,400 US gal), 4-long-ton (4.1 t) tender.

Due to weight restrictions it proved to be impossible for all three cylinders to drive the middle coupled axle, the design used divided drive with the middle cylinder driving the leading axle and was positioned forward above the front bogie. The LNER also ordered some modifications, including an increase in cylinder size from 17 in (432 mm) to 17 ¹⁄₂ in (444 mm), and a lengthening of the firebox by 5 in (127.0 mm) with longer frames, and lighter springs. The design continued to prove problematic and the LNER eventually cancelled a penalty clause in the original contract. The first locomotive, No. 2802 Walsingham was delivered 30 November 1928, thirteen weeks late.