South African Class Experimental AC

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 E1600, was withdrawn from revenue service for use as an experimental 25 kV AC locomotive.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.^[1]

Manufacturer

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.^[2]

Bogies

Series 2 to 11 bogies

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.^[3]

Orientation

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.^[1]

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 E1600 was permanently withdrawn from revenue service in 1978, rebuilt as a test-bed for use during 25 kV AC electrification and reclassified to the sole Class Experimental AC.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:^[1][3][4]

• 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.

No. E1600's works plates

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.^[3]

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.^[1][3]

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.^[3]

Illustration

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

References

Wikimedia Commons has media related to South African Class Exp/AC.

Locomotives of South Africa
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Electric	Amcoal Class E38 SAR Class ES SAR Class ES1 SAR Class Exp-AC SAR Class 1E SAR Class 2E SAR Class 3E SAR Class 4E SAR Class 5E s1 SAR Class 5E s2 SAR Class 5E s3 SAR Class 5E1 s1 SAR Class 5E1 s2 SAR Class 5E1 s3 SAR Class 5E1 s4 SAR Class 5E1 s5 SAR Class 6E SAR Class 6E1 s1 SAR Class 6E1 s2 SAR Class 6E1 s3 SAR Class 6E1 s4 SAR Class 6E1 s5 SAR Class 6E1 s6 SAR Class 6E1 s7 SAR Class 6E1 s8 SAR Class 6E1 s9 SAR Class 6E1 s10 SAR Class 6E1 s11 SAR Class 7E SAR Class 7E1 SAR Class 7E2 s1 SAR Class 7E2 s2 SAR Class 7E3 s1 SAR Class 7E3 s2 Spoornet Class 7E4 SAR Class 8E SAR Class 9E s1 SAR Class 9E s2 SAR Class 10E SAR Class 10E1 s1 Spoornet Class 10E1 s2 SAR Class 10E2 SAR Class 11E SAR Class 12E Spoornet Class 14E Spoornet Class 14E1 TFR Class 15E Spoornet Class 16E Spoornet Class 17E Spoornet Class 18E s1 TFR Class 18E s2 TFR Class 19E TFR Class 20E TFR Class 21E TFR Class 22E
Gas-electric	SAR Gas-electric
Diesel	3' 6" gauge Diesel-electric PRASA Class Afro 4000 SAR Class DS SAR Class DS1 SAR Class 31-000 SAR Class 32-000 SAR Class 32-200 SAR Class 33-000 SAR Class 33-200 SAR Class 33-400 SAR Class 34-000 SAR Class 34-200 SAR Class 34-400 SAR Class 34-500 SAR Class 34-600 SAR Class 34-800 SAR Class 34-900 SAR Class 35-000 SAR Class 35-200 SAR Class 35-400 SAR Class 35-600 TFR Class 35-800 SAR Class 36-000 SAR Class 36-200 SAR Class 37-000 Spoornet Class 39-000 TFR Class 39-200 TFR Class 43-000 TFR Class 44-000 2' gauge Diesel-electric SAR Class 91-000 3' 6" gauge Diesel-hydraulic SAR Class 61-000 3' 6" gauge Electro-diesel Spoornet Class 38-000
List of South African locomotive classes South African locomotive numbering and classification