they were used on Central section trains to Portsmouth and Southampton until replaced by V class locomotives. The U1 class worked troop trains along this route during the Second World War, proving their worth as rugged locomotives. However, a trial on the Somerset and Dorset proved that the design was not good on steep gradients, and was thus confined to the Central and Eastern sections of the Southern Railway network. Crews praised their ability to achieve what they were designed to do, being thoroughly at home with the secondary duties that suited such a locomotive. The class was to be the final member of Maunsell's series of moguls, but the off-cuts from the rebuilding of the K class and a similar boiler were used on yet another of the "family" of standardized locomotives, the 3-cylinder W class 2-6-4 heavy freight tank engine. All locomotives were inherited by British Railways in 1948, and from 1955, several members of the class received new chimneys of the British Railways Standard Class 4 variety and replacement cylinders, which had become worn through intensive use. No major redesign of the front-end of the U1 class was required, with all the steam passages fully streamlined as a result of experience with the previous five Maunsell designs. The U1 Class members working on the Hastings route were subjected to excess flange wear because of the tight curves, a problem also experienced when used on the network west of Exeter, when the aging T9 class 4-4-0 locomotives designed by Dugald Drummond were finally withdrawn from service in the early 1960s. The locomotive crews of the area took a dislike to the U1 in preference to the smaller-wheeled N class, which performed better on the steeper gradients found in this part of the railway network. With the electrification of the Kentish main lines of the Eastern section, the amount of work that required the U1 class' route availability advantage was reduced, and the class was congregated at Stewarts Lane shed in London. The majority of the class was withdrawn from service in 1962, with the final three (including the prototype) gone by June 1963, outlasting their N1 class siblings by one year. Having been replaced by Bulleid's Light Pacifics, no members of the U1 class were preserved. Livery and numbering Southern The entire class was painted in Maunsell's lined Southern Railway Olive Green with yellow markings and "Southern" on