Seen here at Newcastle , 60111 " Enterprise " was rather a special engine , having in 1927 been the very first effective " A3 " , the first of five " A1 ' s " rebuilt by Sir Nigel Gresley that year with higher pressure boilers , enlarged superheaters and modified valve settings in an effort to improve performance and reduce coal consumption .
Sir Nigel had for some earlier years been anxious to enhance the performance of his highly successful and original " A 1 's " and he had concentrated his efforts following the 1924 British Empire Exhibition and the 1925 Locomotive Exchanges , both of which had seen comparisons drawn between his own design of class " A 1 " express passenger locomotives and the " Castles " of the Great Western Railway .
Although slowed during the War Years , rebuilding of the "A 1' s " to " A 3 's " continued until 1949 when British Railways acquired from the L.N.E.R. fifty such rebuilds and just one unrebuilt and original " A 1 " , namely 2567 , later 68 , " Sir Visto " which was rebuilt by them in 1949 and renumbered 60068 .