By the mid 1920s there was a critical need for locomotives suitable for the increasing passenger traffic on the Great Eastern District (formerly Great Eastern Railway) but track limitations prevented the transfer of locomotives from other regions. Nigel Gresley was required by the LNER to produce a 4-6-0 design to supplement the existing Holden designed B12 locomotives serving that region. Initial specifications were for a three cylinder 4-6-0 which borrowed the cylinder and motion arrangement of the D49 4-4-0 with a tractive effort of approximately 25,000lbs and a restricted axle loading of 17 tons but was eventually increased to 18 tons. The Doncaster Works had many problems meeting the design specifications and the contract was eventually awarded to the North British Locomotive Company (Glasgow) in December 1927.
The final design of the Gresley designed B17s incorporated many features of the A1 Pacifics built in 1924 but several key modifications were required before the first B17 was delivered in late 1928. Between the years of 1930 and 1937 Robert Stephenson & Co. at Darlington and Glasgow produced a total of 73 B17s.
Continuous modifications throughout the building programme resulted in four sub classes B17/1 B17/4. One of the many teething problems suffered by the Class included cracked frames and an attempt to cure this resulted in the B17/2 sub class which had lighter driving axlebox springing and stiffer bogie springs, however the problems still continued. Further modifications included horn blocks in place of guides on the middle axle resulting in another sub class, B17/3. Despite further attempts to improve their springs the Class was always considered to be a rough rider.
The final B17s to be built, B17/4 were intended for routes with fewer length restrictions and therefore were coupled to 4,200 gallon LNER Group Standard tenders. The Holden designed B17s of which there were three sub classes were merged in 1937 becoming B17/1 locomotives and were coupled to 3700 gallon GE tenders. Between 1943 and 1958, 55 of the Class underwent further modifications, including the fitting of Diagram 100A boilers creating yet another sub class, B17/6. The first 47 of the Class were named after English Country Houses with the majority of those remaining being named after football teams resulting in the Class being known as Sandringhams or Footballers.
Locomotive 2846, Gilwell Park was outshopped on the 23rd August 1935 from the LNER Darlington Works. On passing to BR in 1948 the locomotives number was changed to 61646 and was one of the Class that was modified from being a B17/1 to a B17/6 in February 1951. After nearly 24 years service the locomotive was withdrawn on the 9th January 1959 and was cut up at the BR Doncaster Works later that month. Unfortunately there are none of the Class preserved.
Designer: Sir Nigel Gresley
Entered Service: 1928
Purpose: Express Passenger
Wheel Configuration: 4-6-0