 Electrification and the transfer of locomotives from other areas were the first real threats towards the class's survival, some spending time in store, and the first withdrawals taking place from 1933.However, they were fitted for working motor trains (otherwise known as Push-pull trains) by the Southern during the 1930s to replace D1 tanks, although the D3 were considered rougher riding.During World War II, on 26 November 1942, one engine, number 2365, was working an afternoon New Romney to Ashford passenger train through the Romney Marshes near Lydd when she was attacked by a low-flying German fighter aircraft.