In 1976 and 1977, the South African Railways placed one hundred Class 6E1, Series 6 electric locomotives with a Bo-Bo wheel arrangement in mainline service.

[1] The 3 kV DC Class 6E1, Series 6 electric locomotive was designed and built for the South African Railways (SAR) by Union Carriage & Wagon (UCW) in Nigel, Transvaal.

A pantograph hook stick was stowed in a tube mounted below the lower edge of the locomotive body on the roof access ladder side.

While some Class 6E1 series are visually indistinguishable from their predecessors or successors, some externally visible changes did occur over the years.

1 end was stripped of all controls and the driver's front and side windows were blanked off to have a toilet installed, thereby forfeiting the locomotive's bi-directional ability.

The fact that the handbrake was located in cab 2 was not a deciding factor, but was considered an additional benefit.

Some reports indicated that the incomplete units would be forwarded to Danskraal or Durban for completion, but it could not be confirmed that this actually took place.

In the 1990s many of the Series 6 units began to be repainted in the Spoornet orange livery with a yellow and blue chevron pattern on the cowcatchers.