South African Class 6E1, Series 8

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South African Class 6E1, Series 8
SAR Class 6E1 Series 8 E1973.JPG
No. E1973 leading the Premier Classe at Stikland, Cape Town, 17 November 2006
Type and origin
Power type Electric
Designer Union Carriage & Wagon
Builder Union Carriage & Wagon
Model UCW 6E1
Build date 1979-1981
Total produced 105
Specifications
UIC classification Bo-Bo
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)
Current collection
method
Pantographs
Traction motors Four AEI 283 AY
Transmission 18/67 gear ratio
Performance figures
Maximum speed 115 km/h (71 mph)
Power output Per motor:
623 kW (835 hp) 1 hour
563 kW (755 hp) continuous
Total:
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)
Locomotive brake Air & Regenerative
Train brakes Air & Vacuum
Career
Operator(s) South African Railways
Spoornet
Transnet Freight Rail
PRASA
Class Class 6E1
Power class 3 kV DC
Number in class 105
Number(s) E1896-E2000 [1]
Delivered 1979-1981
First run 1979

The South African Class 6E1, Series 8 of 1979 is a South African electric locomotive from the South African Railways era.

Between 1979 and 1981 the South African Railways placed one hundred and five Class 6E1, Series 8 electric locomotives with a Bo-Bo wheel arrangement in mainline service.[1]

Manufacturer[edit]

The 3 kV DC Class 6E1, Series 8 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).[2]

One hundred and five locomotives were delivered between 1979 and 1981, numbered in the range from E1896 to E2000. UCW did not allocate builder’s or works numbers to the locomotives it built for the SAR, but used the SAR unit numbers for their record keeping.[1]

Characteristics[edit]

Bogies[edit]

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.[3]

Orientation[edit]

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 has three small panels along the lower half of the body and a large hatch door below the second small window to the right of the side door on the roof access ladder side, and only one small panel and a large hatch door below the first window immediately to the right of the door on the opposite side.[1]

Series identifying features[edit]

SAR Class 6E1 Series 8 E1976 ID.JPG

The Class 6E1 was produced in eleven series over a period of nearly sixteen years. While some of the 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 locomotives had their sandboxes mounted along the bottom edge of the locomotive body, with the sandbox lids fitting into recesses in the body.[1]

Series 8 is the only Class 6E1 series with unique visual distinguishing features. It can be distinguished from all earlier series by its large hatch door on each side, below the second small window to the right of the side door on the roof access ladder side, and below the first window immediately to the right of the door on the other side. It can also be distinguished from all subsequent series by the absence of rainwater drainage holes along the lower body sides.[1]

Crew access[edit]

The Class 5E, 5E1, 6E and 6E1 locomotives are notoriously difficult to enter from ground level since their lever-style door handles are at waist level when standing inside the locomotive, making it impossible to open the door from outside without first climbing up high enough to reach the door handle while hanging on to the side handrails with one hand only. Crews therefore often choose to leave the doors ajar when parking and exiting the locomotives.[4]

Series 8 and some late model Series 7 locomotives were equipped with doors on which the outside door latch handle is mounted near floor level, with a simple drawer pull type handle at mid door level.[5]

Operation[edit]

Startup[edit]

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 that 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 that 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[edit]

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 that accelerate the dissipation of heat in the resistor banks give the Class 6E1 its very distinctive sound, a deep and loud whine when power is applied.[7]

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.[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 over short periods. 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.[6]

Brakes[edit]

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.

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.

Service[edit]

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 that covers portions of the Northern Cape, the Free State, Natal, Gauteng, North West Province and Mpumalanga.[8]

Reclassification and rebuilding[edit]

Reclassification to Class 16E[edit]

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 number 1 ends, abandoning the number one end cabs in terms of maintenance and using only the number two end cabs. Most were later either disbanded with the locomotives reverting to Class 6E1 and regaining their original numbers, or getting rebuilt to Class 18E.[8]

Ten known Series 8 locomotives were part of such Class 16E pairs.[8]

  • E1914 and E1915 became 16-503 A and B.
  • E1916 and E1917 became 16-501 A and B.
  • E1918 and E1919 became 16-505 A and B.
  • E1925 and E1926 became 16-504 A and B.
  • E1928 and E1929 became 16-506 A and B.

Modification to Class 17E[edit]

No. E1913 as Class 17E, Capital Park, Pretoria, 28 September 2006

Class 17E locomotives were modified and reclassified from Class 6E1 Series 7, 8 or 9 locomotives during 1993 and 1994. Key modifications included improved regenerative braking and wheel slip control to improve their reliability on the steep gradients and curves of the Natal mainline. Unlike the unmodified but reclassified Class 16E locomotives, the Class 17Es retained their original unit numbers after reclassification.[8]

A stumbling block was that the regeneration equipment at many of the sub-stations along the route was unreliable, and since there was no guarantee that another train would be in the same section to absorb the regenerated energy, there was always the risk that line voltage could exceed 4.1 kV, which would make either the sub-station or the locomotive trip out. As a result the subsequent rebuilt Class 18E locomotives were not equipped with regenerative braking.[9]

Fifty-five known Series 8 locomotives were modified and reclassified to Class 17E. Their unit numbers are displayed in the table below.[8]

Rebuilding to Class 18E[edit]

Cab 1 of Class 18E no. 18-204, ex Class 6E1 no. E1972, Capital Park, Pretoria, 16 May 2013

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 locomotive's bi-directional ability.[8][9]

Brake rack in Class 18E no. 18-089

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.[9]

While the earlier Class 6E1, Series 2 to 7 locomotives had been built with a brake system consisting of various valves connected to each other with pipes, commonly referred to as a “bicycle frame” brake system, the Class 6E1, Series 8 to 11 locomotives were built with an air equipment frame brake system, commonly referred to as a brake rack. Since the design of the rebuilt Class 18E locomotives included the same brake rack, the rebuilding project was begun with the newer series 8 to 11 locomotives in order to reduce the overall cost of rebuilding. [9]

Bar two, all the Class 6E1, Series 8 locomotives that were used in this rebuilding project were rebuilt to Class 18E, Series 1 locomotives. The known numbers and renumbering details are shown in the table.[9]

The Blue Train[edit]

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 the name "SPOORNET" in Spoornet’s orange era, and blue with the Spoornet logo but without the name "SPOORNET" in Spoornet’s maroon era. Later, in Spoornet’s blue era, there was no need for a separate Blue Train livery, while in the Transnet Freight Rail (TFR) era one Class 14E and the surviving Class 14E1 electric locomotives were eventually repainted in blue during 2012 for use with the Blue Train.[8][10][11]

All but eight Class 6E1, Series 8 locomotives were delivered in the SAR Gulf Red and yellow whiskers livery. The eight exceptions, numbers E1950 to E1957, were delivered in blue with yellow whiskers for use with the Blue Train between Cape Town and Beaufort West in the Cape Western region.[3][8]

Four of these blue locomotives were damaged on 24 April 1997 when trains number 81007 and 18008, two Trans-Karoo passenger trains, collided at Gouda. One known additional Series 8 locomomotive, number E1973, was then repainted in Spoornet’s orange era Blue Train livery. The four damaged locomotives were later replaced by eight Class 6E locomotives that were repainted in blue.[8]

Of the four damaged blue locomotives, numbers E1953 and E1956 were scrapped while numbers E1954 and E1955 were rebuilt to the first two Class 18E locomotives in 2000 and 2001, numbered 18-001 and 18-002 respectively.[8]

The main picture shows both versions of the Spoornet Blue Train livery. The leading locomotive, number E1973, is in the orange era livery with the name "SPOORNET" below the emblem on the side, while the trailing locomotive, number E1951, is in the maroon era livery without the name "SPOORNET" below the emblem on the side.[10][11]

Liveries illustrated[edit]

Illustrated below are some of the other liveries that Class 6E1, Series 8 locomotives served in.

See also[edit]

References[edit]

  1. ^ a b c d e f 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
  2. ^ "UCW - Electric locomotives". The UCW Partnership. Archived from the original on 12 October 2007. Retrieved 30 September 2010. 
  3. ^ a b Paxton, Leith; Bourne, David (1985). Locomotives of the South African Railways (1st ed.). Cape Town: Struik. pp. 128–129. ISBN 0869772112. 
  4. ^ E1882 with high mounted door handle
  5. ^ E1898 with low mounted door handle
  6. ^ a b c d e Operation - South African Classes 6E, 6E1, 16E, 17E and 18E
  7. ^ Dulez, Jean A. (2012). Railways of Southern Africa 150 Years (Commemorating One Hundred and Fifty Years of Railways on the Sub-Continent - Complete Motive Power Classifications and Famous Trains - 1860-2011) (1st ed.). Garden View, Johannesburg, South Africa: Vidrail Productions. p. 297. ISBN 9 780620 512282. 
  8. ^ a b c d e f g h i j Railways of Southern Africa Locomotive Guide, 2002 Edition, (Compiled by John N. Middleton), p57, as amended by Combined Amendment List 4, January 2009
  9. ^ a b c d e 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
  10. ^ a b E1973 in blue based on orange livery
  11. ^ a b E1951 in blue based on maroon livery