In 1905, two rack tank locomotives were built for the CSAR by Vulcan Foundry, for use on the steep rack section between Waterval Onder and Waterval Boven on the line to Mozambique. Designed as two-cylinder locomotives by Hyde, the design was modified by the builders to four cylinders with the inside cylinders driving the rack equipment, but without a compensating increase in boiler capacity. The locomotives were failures on the rack section, their rack equipment was removed within a year of entering service and they were reassigned to shunting duty. In 1912, they were considered obsolete by the SAR and not classified, but they remained in service until 1915.