Gresley’s A4sGresleys A4s 27. 50 A remarkable collection featuring rare colour and black and white images that documents this most popular class of locomotive. Gresleys A4s captures these world famous locomotives throughout their life, with over 300 excellent colour and black and white images present in this collection, which is arguably the greatest ever assembled on the class. In the mid 1930s, eminent locomotive engineer Sir Nigel Gresley produced plans for the