South African Class 6E1, Series 5
|South African Class 6E1, Series 5|
|Designer||Union Carriage and Wagon|
|Builder||Union Carriage and Wagon|
|Number rebuilt||1 to experimental AC|
|Gauge||3 ft 6 in (1,067 mm) Cape gauge|
|Bogies||3.430 m (11 ft 3 in) wheelbase|
|Wheel diameter||1,220 mm (48 in)|
|Wheelbase||11.279 m (37 ft 0.1 in)|
|Length||15.494 m (50 ft 10 in)|
|Width||2.896 m (9 ft 6 in)|
|Height||4.089 m (13 ft 5 in) pantographs down|
|Axle load||22,226 kg (21.9 long tons)|
|Locomotive weight||88,904 kg (87.5 long tons)|
|Traction motors||Four AEI 283 AZ|
|Transmission||18/67 gear ratio|
|Top speed||113 km/h (70 mph)|
|Power output||Per motor:
623 kW (835 hp) 1 hour
563 kW (755 hp) continuous
2,492 kW (3,342 hp) 1 hour
2,252 kW (3,020 hp) continuous
|Tractive effort||311 kN (70,000 lbf) starting
221 kN (50,000 lbf) 1 hour
193 kN (43,000 lbf) continuous at 40 km/h (25 mph)
|Train brakes||Air & Vacuum|
|Operator(s)||South African Railways
Transnet Freight Rail
|Power class||3 kV DC|
|Number in class||99|
|Number||E1546-E1599, E1601-E1645 |
Between 1974 and 1976 the South African Railways placed one hundred Class 6E1, Series 5 electric locomotives with a Bo-Bo wheel arrangement in mainline service. One of them was later withdrawn from revenue service for use as an experimental 25 kV AC locomotive.
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 the General Electric Company (GEC).
One hundred locomotives were delivered between 1974 and 1976, numbered in the range from E1546 to E1645. UCW did not allocate builder’s numbers to the locomotives it built for the SAR and used the SAR running numbers for their record keeping.
The Class 6E1 was built with sophisticated traction linkages on their bogies and with stabilisers mounted between the linkages on the bogies and the locomotive body. Together with its electronic wheelslip detection system, these traction linkages and stabilisers ensure the maximum transfer of power to the rails without causing wheelslip.
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. A passage along the centre of the locomotive connects the cabs, which are identical apart from the fact that the handbrake is located in cab 2. A pantograph hook stick is stowed in a tube mounted below the lower edge of the locomotive body on the roof access ladder side.
The locomotive is controlled via resistors over which the voltage is dropped in a configuration of series and parallel electrical circuits. The circuit breakers that switch these circuits work under very high power and voltage and are all pneumatically operated for insulation purposes. Compressed air is required to open or close the switch actions and air is also used for the weak field cam switch that also switches under very high currents.
Upon starting off and in the low notches the major part of the voltage is dropped over the banks of resistors and all four traction motors are in series. As the driver notches up, some of the resistor banks are cut out via the pneumatically operated switches and the voltage increases across the traction motors. The more resistors that are cut out as the driver notches higher, the more power is developed by the traction motors. At around 22 to 28 kilometres per hour (14 to 17 miles per hour) the locomotive switches to a parallel combination, where the two traction motors per bogie are in a series electrical circuit while the two bogies are in parallel electrical circuit. Eventually, when all resistors are cut out, the locomotive is operating in full-field.
Series identifying features
The Class 6E1 was produced in eleven series over a period of nearly sixteen years, with altogether nine hundred and sixty units placed in service, all built by UCW. This makes the Class 6E1 the most numerous single locomotive class ever to have seen service in South Africa and serves as ample proof of a highly successful design.
While some Class 6E1 series are visually indistinguishable from their predecessors or successors, some externally visible changes did occur over the years. Series 1 locomotives had their sandboxes mounted on the bogies, while Series 2 to 11 had their sandboxes mounted along the bottom edge of the locomotive body, with the sandbox lids fitting into recesses in the body.
The Series 3 to Series 5 locomotives are visually indistinguishable from each other, the only externally visible difference being the narrower stirrup middle step below the side doors of the first fifty Series 3 locomotives, those in the number range from E1296 to E1345.
The Class 6E1 family saw service all over both of the Transnet Freight Rail (TFR) 3 kV DC mainline and branchline networks, the smaller Cape Western network between Cape Town and Beaufort West and the larger network that covers portions of the Northern Cape, the Free State, Natal, Gauteng, North West Province and Mpumalanga.
Test bed for 25 kV AC research
One of the one hundred Series 5 units, no. E1600, was withdrawn from revenue service in 1978, rebuilt as a test-bed for 25 kV AC electrification and reclassified to Class Experimental AC. This was done while the electrification of the four isolated 25 kV routes was in progress. E1600 was never returned to revenue service. The four 25 kV AC routes are:
- From Pyramid South to Pietersburg and via Rustenburg to Thabazimbi.
- From Ermelo to Richards Bay.
- From Port Elizabeth to De Aar and from there northward to Kimberley and southward to Beaufort West.
- From East London to Springfontein.
Reclassification and rebuilding
Reclassification to Class 16E
During 1990 and 1991 Spoornet semi-permanently coupled several pairs of otherwise largely unmodified Class 6E1 locomotives, reclassified them to Class 16E and allocated a single running number to each pair, with the individual locomotives in the pairs inscribed "A" or "B". The aim was to accomplish savings on cab maintenance by coupling the locomotives at their number 1 ends, abandoning the number one end cabs in terms of maintenance and using only the number two end cabs.
Two known Series 5 locomotives, numbers E1549 and E1607, were part of such Class 16E pairs and became Class 16E numbers 16-319B and 16-335A respectively.
Rebuilding to Class 18E
Beginning in 2000, Spoornet began a project to rebuild Series 2 to 11 Class 6E1 locomotives to Class 18E, Series 1 and Series 2 at the Transnet Rail Engineering (TRE) workshops at Koedoespoort. In the process the cab at the number 1 end was stripped of all controls and the driver's front and side windows were blanked off in order to have a toilet installed, thereby forfeiting the loco's bi-directional ability.
Since the driving cab's noise level had to be below 85 decibels, cab 2 was selected as the Class 18E driving cab primarily based on its lower noise level compared to cab 1, which is closer and more exposed to the compressor's noise and vibration. Another factor was the closer proximity of cab 2 to the low voltage switch panel. The fact that the handbrake was located in cab 2 was considered an additional benefit.
The Class 6E1, Series 5 locomotives that were used in this project were all rebuilt to Class 18E, Series 2 locomotives. Their numbers and renumbering details are shown in the table.
All the Class 6E1, Series 5 locomotives were delivered in the SAR Gulf Red and yellow whiskers livery. The main picture shows no. E1629 in the Shosholoza Meyl livery of the Passenger Rail Agency of South Africa (PRASA). Illustrated below are some of the other liveries that Series 5 locomotives served in.
No. E1557 in Spoornet orange livery at Slypklip near Warrenton, Northern Cape, 22 September 2006
No. E1564 in the correct Spoornet maroon livery without “SPOORNET” at Beaconsfield, 17 September 2009
No. E1558 in an incorrect Spoornet maroon livery with “SPOORNET” at Orkney, 13 October 2009
- South African Class Exp AC
- South African Class 6E1, Series 1
- South African Class 6E1, Series 2
- South African Class 6E1, Series 3
- South African Class 6E1, Series 4
- South African Class 6E1, Series 6
- South African Class 6E1, Series 7
- South African Class 6E1, Series 8
- South African Class 6E1, Series 9
- South African Class 6E1, Series 10
- South African Class 6E1, Series 11
- South African Class 16E
- South African Class 18E, Series 2
- Electric locomotive numbering and classification
- South African locomotive history
- List of South African locomotive classes
- 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
- Paxton, Leith; Bourne, David (1985). Locomotives of the South African Railways (1st ed.). Cape Town: Struik. pp. 128–129. 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, 57, 60.
- "UCW - Electric locomotives". The UCW Partnership. Archived from the original on 12 October 2007. Retrieved 30 September 2010.
- Operation - South African Classes 6E, 6E1, 16E, 17E and 18E
- E1345 with narrow stirrup
- E1346 with wide stirrup
- Information gathered from the rebuild files of individual locomotives at Transnet Rail Engineering’s Koedoespoort shops, or obtained from John Middleton as well as several Transnet employees