The South African class MF was a 2-6-6-2 Mallet originally ordered by the Central South African Railways (CSAR). They were built by ALCO and based on the MD prototype delivered in 1910, but were superheated. After delivery to South Africa in 1911 in parts, they were erected at Pretoria. Although the Union of South Africa had already been founded at this time, the first nine were still delivered to the CSAR and numbered 1015 to 1023. The last five were directly delivered to the SAR and called class MF No. 1629 to 1633. The first nine were renumbered 1619 to 1627.

While the first nine got an XS tender with ten tons of coal and 5,000 gallons of water, the last five got XM4 tenders with also ten tons of coal, but only 4,000 gallons of water. They were originally used in coal traffic between Witbank and Germiston where they hauled 1,600 tons on inclines of one percent. Between 1923 and 1925, six were simpled. Three of these came to the East London area whey they had to fight 2.5 percent inclines, but apparently without much success. All had been scrapped by 1939.