LNER Class B17

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 Nigel Gresley for hauling passenger services on the Great Eastern Main Line. In total 73 were built.

By 1926, the former GER 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. However, the two designs presented by the NB Loco Co. had an axle loading of 18 tons and 19 tons, respectively. The 18 ton design, being lighter, was chosen. Since it had an axle loading of 18 tons, 1 ton higher than the initial requirement of 17 tons, this meant that the B17’s route availability was “certain GER main lines” instead of the full range which was intended, although the LNER did accept the restriction.

Due to weight restrictions it proved to be impossible for all three cylinders to drive the middle coupled axle. Therefore, 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.

Ten locomotives were built by the North British Locomotive Company (works nos. 23803-12) during November and December, which were allocated the running numbers 2800-9. Five further orders were placed with Darlington Works between December 1928 and March 1935 for a further fifty-two locomotives to be delivered between August 1930 and June 1936. A final batch of eleven were ordered from Robert Stephenson and Company in February 1936 (works nos. 4124-34) for delivery between January and July 1937; resulting in a total of 73 B17s built.

The first ten by the North British Locomotive Company were designated B17, later B17/1. The second and third batches had boilers supplied by Armstrong Whitworth and different springing and became B17/2. The next two batches had different springing and were designated B17/3. However, as the locomotives passed through the works the original springs were replaced by those of the later design and in 1937 the three sub-classes were merged into B17/1. The final Darlington batch introduced in 1936, and those built by Robert Stephenson and Company had 4,200-imperial-gallon (19,000 L; 5,000 US gal), 7.5-long-ton (7.6 t) tenders and were intended for use in the North Eastern area of the LNER: these were designated B17/4.

In September 1937 two locomotives (Nos. 2859 Norwich City and 2870 Tottenham Hotspur) were streamlined in the manner of the LNER Class A4s, renamed East Anglian and City of London and intended for use on the East Anglian train. They were designated B17/5. However, the streamlining was cladding for publicity purposes only and had little effect on the overall speed of the locomotive. By 1951 both engines had been stripped of the streamlining altogether.

Between 1943 and 1957 most of the surviving members of the class were rebuilt with a LNER 100A boiler with increased pressure and were designated B17/6.