A4 Pacific Locomotives

The A4 class of Pacific locos, designed by Sir Nigel Gresley for the LNER in the 1930s, was arguably the most distinctive type of steam locomotive built in Britain. On 3 July 1938 the most famous in the class, Mallard, broke the world speed record for a steam locomotive, travelling at 126mph. This record has never been broken. A total of 35 were built from 1935-38. The efficiency and speed of Gresley's design ensured they continued in top link service into the BR era, particularly London-Edinburgh but also in later years on the hilly Glasgow-Aberdeen route. In 2013, to mark the 75th anniversary of Mallard's record breaking run, all six surviving A4s were gathered together in the UK for the first time since the 1960s and fittingly Bittern set a new world speed record of 93mph for a preserved steam locomotive. This is a history of the construction, design and service of the A4s for over 30 years with the LNER and BR, and an account of the career of the six A4s in preservation.