Built in Doncaster in 1938, 4468 Mallard is a member of arguably Sir Nigel Gresley’s finest express locomotive class – the A4 pacific. It was designed with speed in mind and unlike the LMS Coronation/Duchess class the streamlining was an intrinsic part of the design – not a shell. The A4 class were tested in wind tunnels and designed to work at speeds in excess of 100mph (though speeds above 90mph were not common in everyday working). The streamlining did much to make it look striking, however streamlining alone wasn’t the key to the type’s success.
Internal streamlining to the steam circuit, a higher boiler pressure (250psi) and combustion chamber formed by a firebox extension were key to the efficient power of the type. Having three cylinders also benefited the class as it gave it stability at speed. 4468 Mallard was the first to have a double Kylchap chimney fitted; which made it steam even better than it’s classmates at the time.
4468 Mallard made it’s famous speed record-breaking run when it was five months old and therefore in perfect just run-in condition. On 3rd July 1938. Pulling six coaches and a dynamometer car with Joe Duddington and Inspector Sid Jenkins in charge; 4468 Mallard ran downhill Stoke Bank and attained a speed of 125.88mph. It still holds this world record today and 2013 marks the 75th anniversary of the breaking of the record. To celebrate, all six surviving A4’s will meet at York in July – something that shall be reported here at http://www.locoyard.com!
4468 Mallard did not complete it’s journey to Kings Cross after breaking the record on 3rd July 1938 and retired at Peterborough due to a problematic big end bearing for the middle cylinder. This did not mark the end of the locomotive’s career – that would last for almost one and a half million miles! Renumbered 22 in 1943, Mallard became 60022 in 1948 when LNER was absorbed into the newly nationalised British Railways. Withdrawn in 1963, Mallard became a member of the National Railway Museum. Since then, Mallard has steamed for a short period, but has spent most of it’s time in York on display.
Note that a review of Hornby’s super-detail A4 model can be found here.