A single experimental locomotive was included with the order for nine Class MF Mallet articulated compound steam locomotives which were delivered to the Central South African Railways (CSAR) by the American Locomotive Company (ALCO) in 1911 [REF].
It was similar to the other nine engines, but used saturated instead of superheated steam, had a mechanical stoker and the coupled wheels on the leading engine unit were of a larger diameter than those of the trailing engine unit.