 When the requirement for modern freight locomotives on the Southern increased during the Second World War, Bulleid was faced with the options of continuing the production of the Q Class, or to design a completely new locomotive.Taking the latter option, Bulleid designed what was to become the highly utilitarian SR Class Q1 0-6-0 locomotives.In common with most Maunsell designs, the Q class locomotives were reliable, but there were complaints of poor steaming when used on main-line trains (for which they were never designed).