Between March 1976 and May 1980, the South African Railways placed one hundred Class 35-400 General Electric type U15C diesel-electric locomotives in branch line service.

An externally visible modification which was done during major overhauls is the addition of a saddle hood astride the long hump of the Class 35-000.

The GE Class 35-400 was designed to operate on light rail and they work on most branch lines in the central, western, southern and southeastern parts of the country.

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

These locomotives were sometimes marked 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.

The locomotives did not appear to be restricted to work in any one of the three operations sections and have been observed being transferred between Zimbabwe and Zambia across the bridge at Victoria Falls as required.

In the 1990s many of the Class 35-400 units began to be repainted in the Spoornet orange livery with a yellow and blue chevron pattern on the buffer beams.