This class was intended to haul secondary passenger trains, especially in the south
London suburbs, and twenty locomotives were constructed by
Brighton works between June 1906 and December 1907. The locomotives proved to be reliable but with disappointing performance in their original form, being poor steamers, but all of them passed to the
Southern Railway in 1923. They reportedly gained the nickname "Wankers" due to the aforementioned steaming issues, but were also known as 'Wealden Tanks'. ==I1X class==