In 1983 and 1984, the South African Railways placed sixty Class 7E3, Series 1 electric locomotives with a Co-Co wheel arrangement in mainline service.

[2] In the period from the early 1990s until about 2007, various modifications to improve downhill braking capacity were done to the Coalink line's Hitachi-designed locomotives.

The electrical equipment was designed for high power factor operation, obtained by the switching in of power-factor correction capacitors.

The Class 7E4 locomotives all serve on the 25 kV AC Coalink line from Ermelo via Vryheid to the Richards Bay Coal Terminal.

[1][3] In the SAR and Spoornet eras, when the official liveries were Gulf Red and yellow whiskers for the SAR, and initially orange and later maroon for Spoornet, many selected electric locomotives and some diesel-electrics were painted blue for use with the Blue Train, but without altering the layout of the various paint schemes.