to assist the restoration of classmate 4498 Sir Nigel Gresley. It was scrapped in 1973 as being surplus to requirements, by which time it had also donated parts to the restoration of A3 class locomotive 4472 Flying Scotsman, which had recently returned from America and was being restored at Derby Workshops. Mallard was allocated to three sheds during its career: Doncaster, transferring on 21 October 1943 to Grantham and on 11 April 1948 to Kings Cross Top Shed. 1938 speed record On 3 July 1938, Mallard claimed the world speed record for steam locomotives at during a trial run of a new, quick-acting brake, known as the Westinghouse QSA brake. The speed was achieved during the downward grade of Stoke Bank, south of Grantham at milepost 90¼, between Little Bytham and Essendine stations. Mallard hauled a seven-coach train, including a dynamometer car which housed apparatus to record the speed. The speed it recorded exceeded the previous record speed of set in Germany in 1936 by DRG Class 05 No. 002. Mallard was just four months old at the time of the record, and was operated by driver Joseph Duddington, a man renowned within the LNER for taking calculated risks, and fireman Thomas Bray. Upon arrival at London King's Cross, driver Duddington and inspector Sid Jenkins were quoted as saying that they thought a speed of 130 mph would have been possible if the train did not need to slow for a set of junctions at Essendine. There was also a permanent speed restriction of 15 mph just north of Grantham station, which slowed the train as they sought to build up maximum speed for the descent of Stoke Bank. The A4 class previously had problems with the big end bearing for the middle cylinder, so the big end was fitted with a "stink bomb" of aniseed oil which would be released if the bearing overheated. After attaining the record speed, the middle big end on Mallard did overheat reduced speed, running at onwards to Peterborough, and was sent to Doncaster Works for repair. This had been foreseen by the publicity department, who had many pictures taken for the press, in case Mallard did not make it back to Kings Cross. The (Edwardian period) Ivatt Atlantic that replaced Mallard at Peterborough was only just in sight when the head of publicity started handing out the pictures. Mallard topped Stoke Bank at