High Quality Content by WIKIPEDIA articles! In March 1910 the Central South African Railways placed ten Class 10-2 steam locomotives with a 4-6-2 Pacific wheel arrangement in service, of which five were built with and five without superheaters. In 1912, when the five superheated locomotives were assimilated into the South African Railways, they were renumbered and reclassified to Class 10B. In 1912 the South African Railways placed five more Class 10B locomotives in service.