South African Class 6E1, Series 2

Manufacturer

The 3 kV DC Class 6E1, Series 2 electric locomotive was designed and built for the South African Railways (SAR) in 1971 by Union Carriage and Wagon (UCW) in Nigel, Transvaal, with the electrical equipment supplied by the General Electric Company (GEC).

Fifty locomotives were delivered in 1971, numbered in the range from E1246 to E1295. UCW did not allocate works numbers to the locomotives it built for the SAR and used the SAR unit numbers for their record keeping.

Bogies

The Class 6E1 was built with sophisticated traction linkages on their bogies. Together with the locomotive's electronic wheelslip detection system, these traction struts, mounted between the linkages on the bogies and the locomotive body and colloquially referred to as grasshopper legs, ensure the maximum transfer of power to the rails without causing wheel-slip, by reducing the adhesion of the leading bogie and increasing that of the trailing bogie by as much as 15% upon starting off. This feature was controlled by electronic wheel-slip detection devices and an electric weight transfer relay, which reduced the anchor current to the leading bogie by as much as 50A in notches 2 to 16.

Brakes

The locomotive itself used air brakes, but it was equipped to operate trains with air or vacuum brakes. While hauling a vacuum braked train, the locomotive's air brake system would be disabled and the train would be controlled using the train brakes alone to slow down and stop. While hauling an air braked train, on the other hand, the locomotive brakes would engage along with the train brakes. While working either type of train downgrade, the locomotive's regenerative braking system would also work in conjunction with the train brakes.

When the locomotive was stopped, the air brakes on both bogies were applied together. The handbrake or parking brake, located in Cab no. 2, only operated on the unit's last axle, or no. 7 and 8 wheels.

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, 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 has three small panels along the lower half of the body on the roof access ladder side, and only one panel on the opposite side.

Series identifying features

The Class 6E1 was produced in eleven series over a period of nearly sixteen years, with altogether 960 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 fifty Series 2 and the first fifty Series 3 locomotives are visually indistinguishable from each other. On the Series 3 locomotives in the number range from E1346 to E1445, an externally visible difference is a wider stirrup middle step below their side doors. This appears to indicate that Series 2 should actually have consisted of one hundred locomotives and not fifty, firstly since these locomotives, numbers E1246 to E1345, are identical in exterior appearance, and secondly since Series 4, 5 and 6 were all delivered in batches of one hundred.

Had that been the case, Series 2 and 3 would also have consisted of 100 locomotives each, numbers E1246 to E1345 and E1346 to E1445 respectively, instead of 50 and 150 as they were officially designated, numbered E1246 to E1295 and E1296 to E1445 respectively.

Service

The Class 6E1 family saw service all over both of the 3 kV DC mainline and branchline networks, the smaller Cape Western network between Cape Town and Beaufort West and the larger network which covers portions of the Northern Cape, the Free State, Natal, Gauteng, North West Province and Mpumalanga.

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 locomotive 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 no. 1 ends, abandoning the no. 1 end cabs in terms of maintenance and using only the no. 2 end cabs.

One such pair was made up of two Series 2 locomotives, numbers E1272 and E1273, which became Class 16E no. 16-100A and B 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 no. 1 end was stripped of all controls, to have a toilet installed, thereby forfeiting the unit'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 not a deciding factor, but was considered an additional benefit.

The known Class 6E1, Series 2 locomotives which were used in this project, were all rebuilt to Class 18E, Series 2. Their numbers and renumbering details are listed in the table.

Illustration

The main picture shows no. E1252, in Spoornet orange livery, at Sentrarand locomotive depot in Gauteng. Illustrated below are some of the other liveries which Series 2 locomotives served in.