In 1978, E1600 was withdrawn from revenue service and rebuilt as a test-bed for use during 25 kV AC electrification and reclassified to the sole Class Experimental AC. It was used for testing to detect and eliminate potential problems during the electrification of the four isolated 25 kV networks. These networks are: • Pyramid South to
Pietersburg and via
Rustenburg to
Thabazimbi •
Ermelo to
Richards Bay •
Port Elizabeth via
Noupoort to
De Aar and from there northward to
Kimberley and southward to
Beaufort West •
East London to
Springfontein The unit's single
pantograph and its electronic and electric equipment were manufactured by the 50 c/s Group, a consortium consisting of
ACEC of Belgium,
AEG-Telefunken and
Siemens of Germany,
Alsthom-Atlantique and Société MTE of France, and
Brown Boveri of Switzerland. The same consortium also designed the 25 kV AC
Class 7E locomotives which were placed in service on the four 25 kV networks. The vacuum circuit breaker was supplied by GEC. The original Class 6E1 AEI-283AZ traction motors, manufactured by
Associated Electrical Industries, were retained and the locomotive used a thyristor-diode rectifier set for the traction motor DC power supply. Mechanical components were supplied by UCW. Apart from the inscriptions painted on the locomotive sides, the Class Experimental AC locomotive can be visually distinguished from regular Class 6E1 locomotives by the single pantograph on its no. 2 end instead of the usual two pantographs, one on each end, as well as by the large grilles on the sides. The Class 6E1 has two large grilles to the right of centre on each side while no. E1600 has only one such grille on the roof access ladder side and three on the opposite side. ==References==