Over the period the cost of each engine rose from £14,893 to £16,190. Vulcan Foundry contributed 50 at £15,300 apiece. Orders for the B1s, which became Nos. 61000–61409 under British Railways, totalled 410. The B1s operated throughout LNER territory. The first batch was distributed among depots on the former Great Eastern Railway section: Ipswich, Norwich, and Stratford in London. They were an immediate success and were soon working the Liverpool Street - Harwich boat trains, the "Hook Continental", the "Day Continental" and the "Scandinavian". B1s were also a familiar sight on other top-link workings such as "The East Anglian", "The Broadsman" and "The Fenman". During the 1950s over 70 B1s were stationed on ex-GE lines. They enjoyed similar popularity on ex-Great Northern and Great Central territory. Engines based at Darnall, Sheffield were regularly rostered for the "Master Cutler" and "South Yorkshireman" expresses. Elsewhere there were substantial allocations in Scotland, West Yorkshire and East Yorkshire. If any fault is to be highlighted on the B1, it must be the ride quality. O.S. Nock often criticised the B1s for a poor ride, not something many were used to on the Gresley engines. The B1 was very cheap to build, but the final result was an engine that was somewhat lacking in the quality LNER men had come to expect. The two-cylinder layout gave the engines good starting power and excellent hill climbing abilities, but it also caused very bad hunting effects, a result of the use of cut-offs of up to 75% (a 10% advance on Gresley engines), and as such they were less kind on the passengers they carried than the B17s they replaced. Overall, however, it was entirely necessary that the B1s be introduced, because the LNER was operating a large number of engines that were well past their economic life. It was somewhat ironic that among the engines that came under threat with the arrival of the B1s were the ones that Thompson admired the most: the engines of the North Eastern Railway designed by Vincent Raven (his father-in-law).   59 of the 410 locomotives were named. Early B1s were named after species of antelope, whilst later engines were named after members of the board of directors of the LNER.