Between December 1974 and July 1976, the South African Railways placed one hundred Class 34-600 General Motors Electro-Motive Division type GT26MC diesel-electric locomotives in service.

In SAR, Spoornet and Transnet Freight Rail (TFR) service, the Class 34-600s worked on most mainlines and some unelectrified branch lines in the central, eastern, northern and northeastern parts of South Africa.

It had three connected railway operations in Zimbabwe and Zambia which formed a rail link between South Africa and the Democratic Republic of Congo.

These locomotives were sometimes marked or branded as either BBR or LOG or both, but their status, whether leased or loaned, was unclear since they were still on the TFR roster and still often worked in South Africa as well.

By the turn of the millennium, Sheltam locomotives were operating at Randfontein Estates Gold Mine in Gauteng, in Mpumalanga at Douglas and Vandyksdrift Collieries and at SAPPI, Ngodwana.

[2][10] Six Class 34-600 locomotives were leased to the Congolese railway, the Chemin de Fer Congo-Ocean (CFCO), where they were renumbered in the range from CC801 to CC806.

[8] Five Class 34-600 locomotives went to Ferrovia Centro Atlântico (FCA) at Divinipolis in Brazil, where they run on 1,000 mm (3 ft 3+3⁄8 in) metre gauge.

[2] Ten Class 34-600 locomotives went to Ferrovia Sul Atlântico (FSA) at Curitiba in Brazil, where they also run on Metre gauge.

In the 1990s many of the Class 34-600 units began to be repainted in the Spoornet orange livery with a yellow and blue chevron pattern on the buffer beams.