The South African Railways Class Experimental 6 4-8-0 of 1906 was a steam locomotive from the pre-Union era in the Cape of Good Hope. In 1906, the Cape Government Railways placed a single experimental 10th Class steam locomotive with a 4-8-0 Mastodon type wheel arrangement in service on its Eastern System. In 1912, when this locomotive was assimilated into the South African Railways, it was renumbered and designated Class Experimental 6.