The class 11 designated 36 2-8-2 locomotives built by North British in 1904. They were designed by P.A. Hyde for freight service on newly upgraded lines with heavier tracks of 80 pounds per yard. It was a modern design with a superheated boiler and had many common parts with the class 10 Pacific. The Belpaire firebox was placed behind the last driving axle and supported by the trailing axle. The second and third driving axles had flangeless wheels to ensure better curve negotiation.

After their delivery, some had to be stored for some time to wait for the upgrade of more lines so that these could carry their axle load of 15.75 tons. When the South African Railways were founded, they were still designated class 11. On the Witbank line, they initially hauled trains of 1,050 tons. Later this was reduced to 900 tons to increase the average speed. It soon showed that the low load of 6 tons and 1 cwt on the leading axle led to bad running characteristics at high speeds.

After more powerful Garratts took over heavy freight service, the Mikados were used for local and shunting service. Unlike many other South African steam locomotives, they never received Watson standard boilers. The last ones were withdrawn from SAR service in 1975, after 71 years. Now 15 were sold for industrial work, most of them to gold mines. Some of these worked until the turn of the millennium when they reached an age of nearly 100 years.