When the Union of South Africa was established on 31 May 1910, the three Colonial government railways (CGR, Natal Government Railways and Central South African Railways) were united under a single administration to control and administer the railways, ports and harbours of the Union.
When these ten locomotives were assimilated into the South African Railways (SAR) in 1912, they were renumbered in the range from 649 to 658 and designated [REF].