South African Class Experimental AC
No. E1600 at Pyramid South, Pretoria, 7 May 2013
The South African Railways Class Experimental AC of 1978 is an electric locomotive.
In 1974 and 1975 the South African Railways placed one hundred Class 6E1, Series 5 locomotives with a Bo-Bo wheel arrangement in mainline service. In 1978, one of them, no. E1600, was withdrawn from revenue service for use as an experimental 25 kV AC locomotive. It was rebuilt and reclassified to Class Experimental AC.
The 3 kV DC Class 6E1, Series 5 electric locomotive was designed and built for the South African Railways (SAR) by Union Carriage and Wagon (UCW) in Nigel, Transvaal, with the electrical equipment supplied by General Electric Company (GEC). One hundred Series 5 locomotives were delivered by UCW in 1974 and 1975, numbered in the range from E1546 to E1645.
To ensure the maximum transfer of power to the rails without causing wheel-slip, the Class 6E1 was built with sophisticated traction links between the bogies and the frames and equipped with electronic wheel-slip detection. These traction struts and linkages were to become a distinguishing feature of most subsequent South African electric locomotive models.
These dual cab locomotives have a roof access ladder on one side only, just to the right of the cab access door. The roof access ladder end is marked as the no. 2 end. A corridor along the centre of the locomotive connects the cabs.
Test bed for 25 kV AC research
Of the 100 Series 5 units produced, no. E1600 was permanently withdrawn from revenue service in 1978, rebuilt as a test-bed for use during 25 kV AC electrification and reclassified to the sole Class Experimental AC.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:
- From Pyramid South to Pietersburg and via Rustenburg to Thabazimbi.
- From Ermelo to Richards Bay.
- From Port Elizabeth via Noupoort to De Aar and, from there, northward to Kimberley and southward to Beaufort West.
- From East London to Springfontein.
The locomotive’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. The 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 on both ends, 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.
The main picture shows the roof access ladder or right side of no. E1600. In the picture below, showing the left side, the traction struts and linkages on the bogies were not installed, since the locomotive was being refurbished at the time.
No. E1600, left side, at Koedoespoort, Pretoria, 9 October 2009
- South African Railways Index and Diagrams Electric and Diesel Locomotives, 610mm and 1065mm Gauges, Ref LXD 14/1/100/20, 28 January 1975, as amended
- "UCW - Electric locomotives" (PDF). The UCW Partnership. Archived from the original (PDF) on 12 October 2007. Retrieved 30 September 2010.
- Paxton, Leith; Bourne, David (1985). Locomotives of the South African Railways (1st ed.). Cape Town: Struik. pp. 128–129, 136. ISBN 0869772112.
- Middleton, John N. (2002). Railways of Southern Africa Locomotive Guide - 2002 (as amended by Combined Amendment List 4, January 2009) (2nd, Dec 2002 ed.). Herts, England: Beyer-Garratt Publications. pp. 50–51, 60.
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