Mallard set its world speed record in 1938.
On 3 July 1938, LNER Class A4 4468 Mallard made its celebrated run down Stoke Bank, south of Grantham in England. The streamlined locomotive was only four months old and had been designed by Nigel Gresley at Doncaster Works for fast express passenger service on the London and North Eastern Railway.
Mallard hauled a seven-coach train that included a dynamometer car, which recorded speed during the trial. The run also tested the new quick-acting Westinghouse QSA brake. Mallard reached the famous peak figure of 126 mph, although technical discussion surrounds whether 125 mph was the more reliable measured maximum. The locomotive’s middle-cylinder big-end bearing overheated afterward, and Mallard was sent to Doncaster for repairs.
The 1938 record followed a German 1936 run by DRG Class 05 No. 002. Mallard’s achievement remains associated with the steam era and has never been officially exceeded by another steam locomotive. The preserved engine is now displayed at the National Railway Museum in York.