When the Union of South Africa was established on 31 May 1910, the three Colonial government railways (CGR, Natal Government Railways (NGR) and Central South African Railways (CSAR)) were united under a single administration to control and administer the railways, ports and harbours of the Union.
Although the South African Railways and Harbours came into existence in 1910, the actual classification and renumbering of all the rolling stock of the three constituent railways were only implemented with effect from 1 January 1912.

In 1912, all but one of these fifty locomotives were assimilated into the SAR, designated Class 6A and renumbered in the range from 441 to 489.

The rest of the CGR's 6th Class locomotives, together with the Classes 6-L1 to 6-L3 locomotives which had been inherited by the CSAR from the Oranje-Vrijstaat Gouwerment-Spoorwegen (OVGS) via the Imperial Military Railways (IMR), were grouped into thirteen more sub-classes by the SAR.
The 4-6-0 locomotives became SAR Classes 6, 6B to 6H and 6J to 6L, the 2-6-2 locomotives became Class 6Y and the 2-6-4 locomotives became Class 6Z.
When the Union of South Africa was established on 31 May 1910, the three Colonial government railways (CGR, Natal Government Railways (NGR) and Central South African Railways (CSAR)) were united under a single administration to control and administer the railways, ports and harbours of the Union. Although the South African Railways and Harbours came into existence in 1910, the actual classification and renumbering of all the rolling stock of the three constituent railways were only implemented with effect from 1 January 1912.
In 1912, all but one of these fifty locomotives were assimilated into the SAR, designated Class 6A and renumbered in the range from 441 to 489.
The rest of the CGR's 6th Class locomotives, together with the Classes 6-L1 to 6-L3 locomotives which had been inherited by the CSAR from the Oranje-Vrijstaat Gouwerment-Spoorwegen (OVGS) via the Imperial Military Railways (IMR), were grouped into thirteen more sub-classes by the SAR. The 4-6-0 locomotives became SAR Classes 6, 6B to 6H and 6J to 6L, the 2-6-2 locomotives became Class 6Y and the 2-6-4 locomotives became Class 6Z.
South African Class 6A 4-6-0