South African Class 6E1, Series 1

The South African Railways Class 6E1, Series 1 of 1969 is an electric locomotive.

In 1969 and 1970, the South African Railways placed twenty Class 6E1, Series 1 electric locomotives with a Bo-Bo wheel arrangement in mainline service. Their limited number and the fact that they entered service before the Class 6E, suggest that the Class 6E1, Series 1 locomotives were obtained as demonstrators, before a decision was made on which of the two classes would be perpetuated.^[1][2]

Manufacturer

The 3 kV DC Class 6E1, Series 1 electric locomotive was designed and built for the South African Railways (SAR) in 1969 and 1970 by Union Carriage and Wagon (UCW) in Nigel, Transvaal, with the electrical equipment supplied by Associated Electrical Industries (AEI) and English Electric (EE).^[3][4]

Twenty locomotives were delivered in 1969 and 1970, numbered in the range from E1226 to E1245. UCW did not allocate builder’s or works numbers to the locomotives it built for the SAR and used the SAR unit numbers for their record keeping.^[1]

Characteristics

Bogies

The twenty Series 1 locomotives are identical to the Class 6E in all respects, including traction motors, power, tractive force and body dimensions. The only obvious visual distinguishing feature to tell the Class 6E1, Series 1 apart, was its new design bogies with their distinctive traction struts and linkages.^[1][5]

Class 6E1, Series 1 bogie

Bogie frame and wheels

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. These grasshopper legs and linkages were to become a distinguishing feature on the bogies of most subsequent South African electric locomotive classes.^[5]

The limited number of Class 6E1, Series 1 locomotives which were placed in service and the fact that they entered service before the Class 6E, suggest that the Series 1 locomotives were obtained as demonstrators for these new bogies to be evaluated, before a decision was made about their continued production.^[2]

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.^[1]

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.^[1][5]

While some Class 6E1 series are visually indistinguishable from their predecessors or successors, some externally visible changes did occur over the years. Like the Classes 5E, 5E1 and 6E, the Class 6E1, Series 1 locomotives had their sandboxes mounted on the bogies, while all the subsequent series Class 6E1s had their sandboxes mounted along the bottom edge of the locomotive body, with the sandbox lids fitting into recesses in the body.^[1][5]

Operation

Startup

When there is no compressed air in the locomotive's system to raise a pantograph to start up, a pantograph hook stick is used to manually raise the pantograph. This starts the high voltage motor, which drives the auxiliary alternator to supply 110V power, to start the compressor and power other control circuits. Once there is enough main air pressure to keep the pantograph in the raised position, the pantograph hook stick can be dropped.^[6]

The locomotive is controlled via resistors, over which the voltage is dropped in a configuration of series and parallel electrical circuits. The circuit breakers which switch these circuits, work under very high power and voltage and are therefore all pneumatically operated for insulation purposes. Compressed air is required to open or close the switch actions and air is also used for the weakfield cam switch, which also switches under very high currents.^[6]

Running

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.^[6] The blowers which, accelerate the dissipation of heat in the resistor banks, give the Class 6E its very distinctive sound, a deep and loud whine when power is applied.^[2]

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 which 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.^[6]

When the traction motors are operated in full-field, be it in series or parallel mode, they are performing at maximum power for normal operation. To increase the speed at this point, if necessary, higher power output is required from the traction motors. The only way to increase power is to force a higher current flow. To accomplish this, the weakfield cam switch switches resistance in parallel with the field coils, which reduces the overall resistance of the field coils. This increases the magnetic flux and more power is generated by the traction motors, over short periods.^[6]

Brakes

The locomotive itself used air brakes, but it was equipped to operate trains with air or vacuum brakes. The brake system would be set up for either air or vacuum train working by means of a turning switch on the driver's brake valve, and by pre-setting the appropriate brake valves in the passage.

Compressed air pipes

The Class 6E1 locomotives were built with an air brake system, consisting of various valves connected to each other with pipes, commonly referred to as a “bicycle frame” brake system. The compressed air pipes run under the locomotive's belly in a zig-zag pattern, going through bolster and other members to extend its length, to allow the maximum amount of moisture to condense on the way to the reservoirs. As a result, it has multiple pipe connections. A weakness of the system was that, after an accident or even a hard coupling, these pipes tended to develop leaks at the joints, which were extremely difficult to repair.^[7]

While hauling a vacuum braked train, the locomotive's air brake system would be disabled and the train would be controlled by 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.

Unlike the Classes 5E and 5E1, whose air brakes could be applied independently on each bogie when the locomotive was stopped, the air brakes on both bogies would be applied together on the Classes 6E and 6E1. The handbrake or parking brake, located in Cab no. 2, only operated on the unit's last axle, or no. 7 and 8 wheels.

Service

The Class 6E1 family saw service all over both of the 3 kV DC mainline and branchline networks.^[3]

Cape Western network

The smaller network is the Cape Western line between Cape Town and Beaufort West, with the locomotives based at the Bellville Depot in Cape Town.^[3]

Northern network

The larger network covers portions of the Northern Cape, the Free State, Natal, Gauteng, North West Province and Mpumalanga, the main routes in this vast area being as follows:^[3]

• From Johannesburg in Gauteng via Kimberley to Hotazel in the Northern Cape.
• From Johannesburg via Kroonstad to Bloemfontein in the Free State.
• From Johannesburg to Durban in Natal.
• From Johannesburg via Pretoria in Gauteng and Witbank in Mpumalanga to Komatipoort on the Mozambique border, as well as to Derwent and Roossenekal.
• From Johannesburg via Springs to Witbank.
• From Johannesburg via Coligny to Lichtenburg.
• From Durban in Natal to Empangeni in the north and Port Shepstone in the south.
• From Ermelo to Ogies and Wonderfontein in Mpumalanga.
• From Kroonstad in the Free State via Bethlehem and Ladysmith to Vryheid in Natal.

The electric locomotives, allocated to depots within this network, are largely pooled and can operate anywhere in the network, as required by the Operating Department, but they return to their home depots for maintenance every twenty-eight days.^[3]

In 2011, the Class 6E1 began to be withdrawn from the Natal corridor (NatCor) line between Johannesburg and Durban, and replaced with Class 18E locomotives.^[3]

In KwaZulu-Natal, the coastal sections from Durban to Empangeni in the north and to Port Shepstone in the south were due to be dieselised at the end of October 2011, using EMD Classes 34 and 37-000 locomotives, which were being displaced by the introduction of new Class 43-000 diesel-electric locomotives on the line from Mpumalanga via Swaziland to Richards Bay.^[8]

In practice, however, electric locomotives were observed at Port Shepstone as late as 24 May 2012, while the diesel power on the South Coast line consisted predomiminantly of Class 37-000 locomotives. The overhead catenary equipment between Stanger and Empangeni and between Kelso and Port Shepstone was to be removed soon after the end of October 2011, but actual removal only took place in November 2013. By October 2014, the catenary masts, sans wiring, were still standing at Port Shepstone.

Illustration

The Series 1 locomotives were all delivered in the SAR Gulf Red livery with yellow whiskers. By c. 2000, they were all repainted in the Spoornet orange livery.

• 

  No. E1227, right side, Beaconsfield, 7 October 2015

• 

  No. E1236, left side, Kaalfontein, 28 September 2009

References

Wikimedia Commons has media related to South African Class 6E1 Series 1.

Locomotives of South Africa Steam 7' ¼" gauge East London Harbour 0-4-0 Table Bay Harbour 0-4-0ST Table Bay Harbour 0-4-0T Table Bay Harbour 0-4-0WT 4' 8½" gauge Cape 0-4-0T Blackie Cape 0-4-2 Cape 2-4-0T CGR 0-4-0ST Aid Natal 0-4-0ST Durban Natal 0-4-0WT Natal Natal 4-4-0T Perseverance 3' 6" gauge Tank engines CGR 0-4-0ST 1873 CGR 0-4-0ST 1874 CGR 0-4-0ST 1881 Coffee Pot CGR 0-6-0ST 1902 CGR 0-6-0T 1876 Back-to-Back CGR 2-6-0ST 1900 CGR 2-6-0ST 1902 CGR 1st Class 0-4-0ST 1875 CGR 1st Class 0-4-0ST 1876 CGR 1st Class 2-6-0ST 1876 CGR 1st Class 4-4-0T 1875 CGR 2nd Class 4-4-0T 1882 CGR 3rd Class 2-6-0T CGR Railmotor CSAR Class C CSAR Class E CSAR Rack CSAR Railmotor DSWA Eight-Coupled Tank 2-8-0T Durban's Congella Durban's Edward Innes Durban's John Milne Durban's Sir Albert Port Elizabeth Harbour 0-4-0ST Kowie Railway 0-6-0T Kowie Railway 4-4-0T Metropolitan & Suburban 4-6-2T NGR 2-6-0T Durban & Pietermaritzburg NGR Class I 2-6-2T NGR Class K 0-4-0ST NGR Class K 0-6-0ST NGR Class K 2-6-0T NZASM 10 Tonner NZASM 14 Tonner NZASM 18 Tonner NZASM 19 Tonner NZASM 32 Tonner NZASM 40 Tonner PPR 26 Tonner PPR 35 Tonner Portuguese SAR 0-4-0ST 1903 SAR 0-4-0T no. 69 SAR Class A SAR Class B SAR Class C SAR Class C1 SAR Class C2 SAR Class D SAR Class E SAR Class F SAR Class G SAR Class H SAR Class H1 SAR Class H2 SAR Class J SAR Class K SAR Clayton Railmotor 3' 6" gauge Tender engines CGR 1st Class 2-6-0 1876 Beyer, Peacock CGR 1st Class 2-6-0 1876 Kitson CGR 1st Class 2-6-0 1879 CGR 1st Class 2-6-0 1891 CGR 1st Class 4-4-0 1879 CGR 1st Class 4-4-0TT 1881 CGR 2nd Class 2-6-2TT 1875 CGR 3rd Class 4-4-0 1883 CGR 3rd Class 4-4-0 1884 CGR 3rd Class 4-4-0 1889 CGR 3rd Class 4-4-0 1898 CGR 3rd Class 4-4-0 1901 CGR 3rd Class 4-4-0 1903 CGR 4th Class 4-4-2 CGR 4th Class 4-6-0TT 1880 CGR 4th Class 4-6-0TT 1882 CGR 4th Class 4-6-0TT 1884 CGR 5th Class 4-6-0 1890 CGR 5th Class 4-6-0 1891 DSWA Eight-Coupled Tender 2-8-0 NGR Havelock NGR Class I SAR Class Exp 1 SAR Class Exp 2 SAR Class Exp 3 SAR Class Exp 4 SAR Class Exp 5 SAR Class Exp 6 SAR Class S SAR Class S1 SAR Class S2 SAR Class 1 SAR Class 1A SAR Class 1B SAR Class 2 SAR Class 2C SAR Class 3 SAR Class 3A SAR Class 3B SAR Class 4 SAR Class 4A SAR Class 5 SAR Class 5A SAR Class 5B SAR Class 6 SAR Class 6A SAR Class 6B SAR Class 6C SAR Class 6D SAR Class 6E SAR Class 6F SAR Class 6G SAR Class 6H SAR Class 6J SAR Class 6K SAR Class 6L SAR Class 6Y SAR Class 6Z SAR Class 7 SAR Class 7A SAR Class 7B SAR Class 7C SAR Class 7D SAR Class 7E SAR Class 7F SAR Class 8 SAR Class 8A SAR Class 8B SAR Class 8C SAR Class 8D SAR Class 8E SAR Class 8F SAR Class 8R SAR Class 8X SAR Class 8Y SAR Class 8Z SAR Class 9 SAR Class 10 SAR Class 10A SAR Class 10B SAR Class 10C SAR Class 10D SAR Class 11 SAR Class 12 SAR Class 12A SAR Class 12B SAR Class 13 SAR Class 14 SAR Class 14A SAR Class 14B SAR Class 14C SAR Class 15 SAR Class 15A SAR Class 15B SAR Class 15C SAR Class 15CA SAR Class 15E SAR Class 15F SAR Class 16 SAR Class 16A SAR Class 16B SAR Class 16C SAR Class 16D SAR Class 16DA SAR Class 16E SAR Class 17 SAR Class 18 SAR Class 19 SAR Class 19A SAR Class 19B SAR Class 19C SAR Class 19D SAR Class 20 SAR Class 21 SAR Class 23 SAR Class 24 SAR Class 25 SAR Class 25NC SAR Class 26 Red Devil 3' 6" gauge Articulated engines CGR Fairlie CGR Kitson-Meyer SAR Class FC SAR Class FD SAR Class GA SAR Class GB SAR Class GC SAR Class GCA SAR Class GD SAR Class GDA SAR Class GE SAR Class GEA SAR Class GF SAR Class GG SAR Class GH SAR Class GK SAR Class GL SAR Class GM SAR Class GMA SAR Class GO SAR Class HF SAR Class KM SAR Class MA SAR Class MB SAR Class MC SAR Class MC1 SAR Class MD SAR Class ME SAR Class MF SAR Class MG SAR Class MH SAR Class MJ SAR Class MJ1 SAR Class U 2' 6" gauge Cape Copper 0-6-0T 1871 Cape Copper Britannia Cape Copper Caledonia Cape Copper Clara Class Cape Copper Condenser Cape Copper Scotia Class Namaqua Copper Pioneer 2' & 600mm gauges ACR Class NG-G16A CGR NG 0-6-0T CGR NG 4-6-2T CGR Type A 2-6-4T CGR Type C 0-4-0T DSWA Class Ha DSWA Class Hb DSWA Class Hc DSWA Class Hd DSWA Jung DSWA Zwillinge NGR Class N 4-6-2T SAR NG 0-4-0T 1899 SAR Class NG1 SAR Class NG2 SAR Class NG3 SAR Class NG4 SAR Class NG5 SAR Class NG6 SAR Class NG7 SAR Class NG8 SAR Class NG9 SAR Class NG10 SAR Class NG-G11 SAR Class NG-G12 SAR Class NG-G13 SAR Class NG-G14 SAR Class NG15 SAR Class NG-G16 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 SAR Class 8E SAR Class 9E s1 SAR Class 9E s2 SAR Class 10E SAR 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