There were also plans for streamlining all the members of the new A1 class, but these were never acted upon, with a logical scenario being due to wartime austerity measures making the additional material requirement of streamlining unacceptable to the LNER Emergency Board. New-build Class A1 In October 1945, the order was given to construct sixteen new locomotives to the new A1 plan. However, before these could be built Thompson had retired and Arthur Peppercorn had taken over as CME and he deferred building them until 1948, by which time he had altered the design to become the Peppercorn Class A1 Pacific design. In 1947 Great Northern, up to then the sole member of the class officially designated Class A1, was reclassified Class A1/1 in anticipation of these new Peppercorn A1s. The A1/1 in service The rebuilt locomotive had excellent steam generation due to utilising an A4 boiler and had a tractive effort of , which made it one of the most powerful pacifics within the LNER, surpassing the Gresley A4 with only the A2/2 surpassing it. In the same year with only three working months, it achieved engine miles, compared to the A4 locomotives working in Scotland, which had the highest mileage that year and averaged . It then went on to become the highest mileage Pacific with an annual figure of , outperforming the next best Gresley Pacific by around . Engine report cards from the LNER archives at the National Railway Museum shows that Great Northern'''s rebuilt form achieved per year, matching Gresley A4s and Peppercorn A1s. For the rest of its working life, Great Northern achieved significantly higher availability than other Pacific classes on the LNER, with its first working year, 1946, achieving 83%. This is partially due to the difference in maintenance approach between the Gresley locomotives, which were often run to failure, while Thompson Pacifics had preventative maintenance and desired high availability. Renumbering Great Northern was renumbered No. 113 under Thompson's 1946 renumbering scheme. It then became No. 60113 during British Railways ownership. Withdrawal 60113 was withdrawn on 19 November 1962 with a badly worn cylinder and was then broken up at Doncaster Works. By the time of its withdrawal, Great Northern achieved the highest mileage out of all the Thompson Pacifics and was one of the best locomotives in terms of overall availability for work. An attempt to save the engine from being