R3974 LNER Thompson Class A2/3 4-6-2 LNER Apple Green 'Airborne' 511 Steam LocomotiveThe A2 3 Class were designed by Edward Thompson as standard express passenger locomotives. After Sir Nigel Gresley's unexpected death in April 1941, Edward Thompson desired to standardise the locomotives of the LNER. This process involved rebuilding locomotives using standard components such as wheel sizes and boiler designs. The A2 3 Class were new built to a similar specification to the A2 2 rebuilds, differing in cylinder sizes and boiler pressure.