Construction of the first 20 engines was shared between Ashford railway works and the Glasgow builder, Sharp, Stewart and Company. By 1907 fifty-one were in traffic. Of these twenty-one were Ashford built while the rest were supplied by outside contractors. The D class was a Harry Wainwright design and he was responsible for the overall look of the engine. The detail work was undertaken by Robert Surtees, his chief draughtsman at Ashford works. Underneath the flowing curves and symmetry of the exterior lay a sure-footed machine that responded well to hard work. Initially the D class was put to work on the Kent coast and Hastings services out of London. By the 1930s the largest allocation of D class 4-4-0s was at Gillingham depot in Kent but they had by now been reduced to secondary train duties and were carrying the livery of the Southern Railway. In 1948 British Railways inherited 28 of the Wainwright 4-4-0s. Their final years saw them concentrated at Guildford in Surrey and the last of the D class, No.31075, was withdrawn from there in 1956. One engine, No.31737, has been preserved and is in its original livery at the National Railway Museum in York.