The GWR 2021 Class was a class of 140 0-6-0ST steam locomotives. They were built at the Wolverhampton railway works of the Great Western Railway between 1897 and 1905. 1897 was the very year of George Armstrong's retirement, so it is uncertain if the design should be attributed to him or to his superior at Swindon, William Dean. In fact the 2021s were simple enlargements of the Armstrong-designed 850 class of 1874. The changes were fundamentally confined to a longer wheelbase to permit fitting of a larger firebox.