The GWR 3252 class, better known as the Duke class, were a series of Great Western locomotives of the 4-4-0 wheel arrangement, built between 1895 and 1899 for passenger work in Devon and Cornwall. All of the Duke class engines were scrapped, and none survive to this day. Only the Earl of Berkeley, a member of the GWR 3200 Dukedog Class, or Earl Class, a cousin class of the GWR 3252 class, is preserved today.
The Dukes were the type of Great Western Engines that Duck described to Peter Sam, telling him how all of them had been scrapped. Peter Sam misunderstood the statement and thought the Duke of Sodor had been scrapped.