The South African Railways Class MD 2-6-6-2 of 1910 was a steam locomotive from the pre-Union era in Transvaal. In March 1910, the Central South African Railways commissioned a single experimental Mallet articulated compound steam locomotive with a 2-6-6-2 wheel arrangement. In 1912, when the locomotive was assimilated into the South African Railways, it was renumbered and designated Class MD.