Between September 1976 and June 1978 the South African Railways placed one hundred Class 35-600 EMD GT18MC diesel-electric locomotives in service. Designed by Electro-Motive Diesel, they were built in two batches by General Motors South Africa in Port Elizabeth, numbered in the ranges 35-601 to 35-650 and 35-651 to 35-700. A single Class 35-600 GT18MC locomotive was also built new in 1977 for Columbus Stainless in Middelburg, Transvaal.
See also the Wikipedia article on the South African Class 35-600.