| South African Class 7E | |
|---|---|
| E7067 at Beaufort West, Western Cape, 2 August 2007 | |
| Power type | Electric |
| Designer | 50 c/s Group |
| Builder | Union Carriage and Wagon |
| Model | 50 c/s Group 7E |
| Build date | 1978-1979 |
| Total produced | 100 |
| UIC classification | Co-Co |
| Gauge | 3 ft 6 in (1,067 mm) Cape gauge |
| Bogies | 4.400 m (14 ft 5.2 in) wheelbase |
| Wheel diameter | 1,220 mm (48.0 in) |
| Wheelbase | 13.800 m (45 ft 3.3 in) |
| Length | 18.465 m (60 ft 7.0 in) |
| Width | 2.896 m (9 ft 6.0 in) |
| Height | 4.200 m (13 ft 9.4 in) pantographs down |
| Axle load | 21,000 kg (20.7 long tons) |
| Locomotive weight | 123,500 kg (121.5 long tons) |
| Current collection method |
Pantographs |
| Traction motors | Six MG 680 |
| Transmission | 20/117 Gear ratio |
| Top speed | 100 km/h (62 mph) |
| Power output | Per motor: 540 kW (720 hp) 1 hour 500 kW (670 hp) continuous Total: 3,240 kW (4,340 hp) 1 hour 3,000 kW (4,000 hp) continuous |
| Tractive effort | 450 kN (100,000 lbf) starting 319 kN (72,000 lbf) 1 hour 300 kN (67,000 lbf) continuous[1] |
| Locomotive brakes | Rheostatic [2] |
| Locomotive brakeforce |
210 kN (47,000 lbf)[3] |
| Train brakes | Air & Vacuum |
| Career | South African Railways Spoornet Transnet Freight Rail Shosholoza Meyl |
| Class | Class 7E |
| Power class | 25 kV 50 Hz AC |
| Number in class | 100 |
| Number | E7001-E7100 |
| Delivered | 1978-1979[1] |
| First run | 1978 |
In 1978 and 1979 the South African Railways placed one hundred Class 7E electric locomotives with a Co-Co wheel arrangement in main line service. They were the first 25 kV AC locomotives to see service on South African rails.[1]
Contents |
The Class 7E 25 kV AC electric locomotive was designed for the South African Railways (SAR) by the 50 c/s Group, consisting of ACEC of Belgium, AEG-Telefunken and Siemens of Germany, Alsthom-Atlantique and Société MTE of France, and Brown Boveri of Switzerland. They were built by Union Carriage and Wagon (UCW) in Nigel, Transvaal, who was the sub-contractor for mechanical components and assembly.[2][4]
One hundred Class 7E locomotives were delivered in 1978 and 1979, numbered E7001 to E7100. Beginning with the Class 7E, the SAR numbering practice was changed to make the class number a part of the locomotive’s running number. From the Class 1E up to the last of the Class 6E1 series of locomotives, all electric locomotives were numbered sequentially from number E1 up.[1]
UCW did not allocate builder’s numbers to the locomotives it built for the SAR. While the practice by most other locomotive builders was to allocate builder’s numbers or works numbers to record the locomotives built by them, UCW simply used the SAR running numbers for their record keeping.[1]
On the Class 7E control of traction and rheostatic braking is by stepless solid-state electronics. The electrical equipment was designed for high power factor operation, obtained by a sector control method.[2]
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 number 2 end. Judging from early photographs of Class 7E locomotives, the distinctive "eyebrow" rainwater beadings above the cab windscreens were added post-delivery.[1]
The Class 7E was designed primarily for goods train service on South Africa’s 25 kV 50 Hz AC electrified lines. Until 1978 all electrified routes in South Africa used 3 kV DC, but from that year all new main line electrification projects bar one used 25 kV AC, the one exception being the 50 kV AC Sishen-Saldanha line. There are four isolated 25 kV routes.[1][2][5]
When it was electrified, the well known double line "race track" between Kimberley and De Aar was single lined and the section was signalled for single-track centralised traffic control (CTC) with long crossing loops. The second set of tracks were left in place, but unelectrified and isolated from the electrified track. However, in anticipation of increased ore traffic to the Eastern Cape from the Sishen branch north-west of Kimberley, work on wiring the second track was to commence in July 2008.[2][5][6]
The Class 7E was placed in service on the coal line from Ermelo to Richards Bay. When later model 25 kV locomotives were introduced, a few Class 7E locomotives went to the Pyramid South and East London lines, but the majority were transferred to the Cape Midlands system to work goods and passenger traffic from Kimberley via De Aar to either Port Elizabeth or Beaufort West. Here the Class 7E finally replaced South Africa’s last big Class 25NC steam locomotives.[2]
A 30c postage stamp depicting a pair of Class 7E locomotives hauling an ore train was one of a set of four commemorative postage stamps that were issued by the South African Post Office on 15 February 1990. The theme illustrated interdependence and regional co-operation in Southern Africa and, in this case, the integrated railway systems that stretched from Cape Town in the south to as far north as Dar es Salaam in Tanzania. The artwork and stamp design was by the noted stamp designer and artist A.H. Barrett.[7]
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. Blue Train locomotives were therefore blue with yellow whiskers in the SAR era, blue with the Spoornet logo and "SPOORNET" in Spoornet’s orange era, and blue with the Spoornet logo but without "SPOORNET" in Spoornet’s maroon era. In Spoornet’s blue era there was no need for a separate Blue Train livery, while in the Transnet Freight Rail (TFR) era the Blue Train was relegated to the very bottom of the railway’s business priority list.
When the section from Kimberley to Beaufort West was electrified, six Class 7E locomotives, numbers E7004 to E7009, were painted blue with yellow whiskers for use with the Blue Train on that section.[5]
The main picture shows E7067 in Spoornet orange livery.
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