Flying Scotsman, designed by Sir Nigel Gresley, was completed at Doncaster Works for the London and North Eastern Railway (LNER) in 1932, initially built as an A1 and carrying the number 1472.

In 1928 an improved Pacific type, classed as A3, appeared and the older A1s were modified to conform to this new improved standard. Flying Scotsmans turn came after WW2 and emerged once again from Doncaster Works on 4th January 1947 as an A3 sporting a long banjo dome type boiler which it still sports today and the number 103. In 1948, on the nationalisation of the railways this number was changed to 60103.

Further modifications to Flying Scotsman include fitting a double Kylchap chimney which helped improve economy and performance; however the extra steam tended to obscure the drivers vision so from 1960 German-style smoke deflectors were fitted.