Who designed the LNER Class A4 streamlined steam locomotives?

Nigel Gresley designed the LNER Class A4 streamlined steam locomotives.

Gresley was chief mechanical engineer of the London and North Eastern Railway and created the A4 for high-speed express passenger service on the East Coast Main Line. The class combined a powerful three-cylinder Pacific arrangement with a smooth, aerodynamic casing inspired partly by contemporary high-speed trains and aircraft design.

Thirty-five A4s were built at Doncaster Works between 1935 and 1938. They hauled prestigious services between London King's Cross, York, Newcastle, and Edinburgh, including the Silver Jubilee and other named expresses. Their streamlined appearance made them among the most recognizable British locomotives.

The most famous A4 is No. 4468 Mallard, which reached 126 mph in 1938 and remains associated with the steam locomotive speed record. The A4s were not designed by George Jackson Churchward, Oliver Bulleid, or William Stanier; those engineers are linked to important locomotive work on other British railways.