Between May 1981 and 1982, the South African Railways placed one hundred Class 37-000 General Motors Electro-Motive Division type GT26M2C diesel-electric locomotives in service.

They work on the Belfast-Steelpoort line and on the manganese route between the Mpumalanga Lowveld and KwaZulu-Natal from Komatipoort through Swaziland to Empangeni and Richards Bay.

Since diesel officially took over the workings at the end of October 2011 and electrics were rarely seen until disappearing from the South Coast completely in March 2012, only the Class 37-000 have been used, normally in sets of three.

[3][4] Although initially well received, the train began to suffer from declining patronage and was eventually cancelled from Monday 30 March 1992, three years after its launch.

39-251 never worked for Transnet and was later reported as sold to RRL, a company which came about out of the abortive joint venture between EMD and Sibanye.

RRL is based at a workshop in the old Pretoria Steel Works complex and several of its locomotives are active in the gold fields around Welkom in the Free State.

[1][5] It was intended to produce one hundred Class 39-000s, but in spite of the technical success of the Transnet Rail Engineering part of the project, rebuilding was halted after completing the first five units due to higher than anticipated cost.

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