test a single prototype, without incurring the expense of building twenty members of the class, if this was the case. The class performed adequately and reliably on the tasks for which they were designed, but were less versatile than might have been hoped. When the requirement for modern freight locomotives on the Southern increased during the Second World War, Bulleid was faced with the options of continuing production of the Q Class, or designing a completely new locomotive. Taking the latter option, Bulleid designed what was to become the highly utilitarian SR Class Q1 locomotives. Modifications 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). In 1940 Bulleid fitted one member of the class with a Lemaître blast pipe in an attempt to improve efficiency. This proved to be successful and the remainder of the class were so fitted between 1946 and 1949. During the 1950s further experiments were carried out with the fitting of a British Railways Standard Class 4 plain blast pipe and small stovepipe chimney to no. 30549 in 1955, resulting in further improvements in both steaming and fuel consumption; in 1958–61 more received the same blast pipe with a BR Standard Class 4 chimney. Operational details and preservation The locomotives were adequate and reliable on secondary services throughout their working lives, their utility compounded by their light weight and steady handling. They were however disappointing on main-line traffic until the draughting was improved after the war. They were fitted with steam carriage heating, and despite being primarily a freight design, periodically deputised in this duty. British Railways inherited the class in 1948 and gave it a 4F power classification, F denoting a freight locomotive in power class 4. Withdrawals from service began during 1962 and were completed by 1965. Loco 30548 served more than 15 years at Bournemouth shed (71B). Preservation The class was not considered sufficiently important for official preservation, and had it not been for Woodham Brothers's scrapyard in Barry, South Wales, no examples would have survived. Only one, number 541 (BR No. 30541), was rescued, and has operated on the Bluebell Railway in Sussex. It is operational in BR Black livery after returning to service in April 2015 (following its absence since 1993). Livery and numbering Southern Railway Due to its primary