"Mallard" is the holder of the world speed record for steam locomotives at . The record was achieved on 3 July 1938 on the slight downward grade of Stoke Bank south of Grantham on the East Coast Main Line, and the highest speed was recorded at milepost 90¼, between Little Bytham and Essendine. It broke the 1936 German (DRG Class 05) 002's record of . The record attempt was carried out during the trials of a new quick-acting brake (the Westinghouse "QSA" brake).