In 1914, Nasmyth, Wilson & Co. delivered eight tank locomotives for shunting to the Uganda Railway which had been designed by Rendel, Palmer and Tritton. Three of these where the 2-6-2T class S, while the other five were the 2-6-4T class MS. The locomotives with a trailing bogie were also suited for short line trips with their larger water and coal supplies. A special feature was a lock-up valve that could be opened to allow the water to distribute in a way that the axle load didn't exceed nine tons.
Around 1920, they were converted to oil-firing. Later in their career with the Kenya-Uganda Railway and the East African Railways, they got an additional water tender and were used on secondary lines. Today 1003 is on static display at Jamhuri Park, Nairobi.