Drummond had 30 freight locomotives built in 1897, which he had designed while still with the Caledonian. Construction eventually took place at Dübs in Scotland and they were nicknamed “Black Motors”. From 1919 all locomotives were fitted with a superheater, with the smoke box being lengthened. This process was continued under the Southern Railway and lasted until 1929. The superheater was partly of the Eastleigh works design and partly of the Maunsell design. Most machines were retired in 1961 and 1962.