South African Class 6E1, Series 7

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South African Class 6E1, Series 7
SAR Class 6E1 Series 7 E1807.JPG
No. E1807 at Kaalfontein, 23 September 2009
Type and origin
Power type Electric
Designer Union Carriage & Wagon
Builder Union Carriage & Wagon
Model UCW 6E1
Build date 1977-1979
Total produced 150
Rebuilder ♠ Transwerk
Transnet Engineering
Rebuild date ♠ 1993-1994 - 2003-2013
Number rebuilt ♠ 14 known to Class 17E
139 to Class 18E, Series 1 & 2
AAR wheel arr. B-B
UIC class Bo'Bo'
Gauge 3 ft 6 in (1,067 mm) Cape gauge
Wheel diameter 1,220 mm (48.0 in)
Wheelbase 11,279 mm (37 ft 0.1 in)
 • Bogie 3,430 mm (11 ft 3.0 in)
Pivot centres 7,849 mm (25 ft 9.0 in)
Panto shoes 6,972 mm (22 ft 10.5 in)
 • Over couplers 15,494 mm (50 ft 10.0 in)
 • Body 14,631 mm (48 ft 0 in)
Width 2,896 mm (9 ft 6.0 in)
 • Pantograph 4,089 mm (13 ft 5.0 in)
 • Body height 3,937 mm (12 ft 11.0 in)
Axle load 22,226 kg (49,000 lb)
Adhesive weight 88,904 kg (196,000 lb)
Loco weight 88,904 kg (196,000 lb)
Power supply Catenary
Current collection Pantographs
Traction motors Four AEI-283AY
 • Rating 1 hour 623 kW (835 hp)
 • Continuous 563 kW (755 hp)
Gear ratio 18:67
Loco brake Air & Regenerative
Train brakes Air & Vacuum
Couplers AAR knuckle
Performance figures
Maximum speed 113 km/h (70 mph)
Power output:
 • 1 hour 2,492 kW (3,342 hp)
 • Continuous 2,252 kW (3,020 hp)
Tractive effort:
 • Starting 311 kN (70,000 lbf)
 • 1 hour 221 kN (50,000 lbf)
 • Continuous 193 kN (43,000 lbf) @ 40 km/h (25 mph)
Operators South African Railways
Transnet Freight Rail
Class Class 6E1
Power class 3 kV DC
Number in class 150
Numbers E1746-E1895
Delivered 1977-1979
First run 1977

The South African Railways Class 6E1, Series 7 of 1977 is an electric locomotive.

Between 1977 and 1979, the South African Railways placed 150 Class 6E1, Series 7 electric locomotives with a Bo-Bo wheel arrangement in mainline service.[1]


SAR Class 6E1 Series 7 E1862 BP.JPG

The 3 kV DC Class 6E1, Series 7 electric locomotive was designed and built for the South African Railways (SAR) by Union Carriage and Wagon (UCW) in Nigel, Transvaal. The electrical equipment was supplied by the General Electric Company (GEC).[2]

The 150 locomotives were delivered between 1977 and 1979, numbered in the range from E1746 to E1895. UCW did not allocate builder’s or works numbers to the locomotives which it built for the SAR and used the SAR unit numbers for their record keeping.[1]



Series 2 to 11 bogies
Bogie frame and wheels

The Class 6E1 was built with sophisticated traction linkages on their bogies. Together with the locomotive's electronic wheel-slip 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 is controlled by electronic wheel-slip detection devices and an electric weight transfer relay, which reduce the anchor current to the leading bogie by as much as 50A in notches 2 to 16.[3]


SAR Class 6E1 Series 7 E1884 ID.JPG

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 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.[4]

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.[4]


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[edit]

Hatchless left side of Series 7 no. E1834
Hatch door on left side of Series 8 no. E1950

The Class 6E1 was produced in eleven series over a period of nearly sixteen years. 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.[1]

The Series 6 and Series 7 locomotives are visually indistinguishable from each other, but can be distinguished from all the older series models by the rainwater beading which was added above the small grilles on the sides just to the right of the side doors. Beginning with Series 8, all subsequent series had a large hatch door on each side to the right of their side doors.[1][3]

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 chose to leave the doors ajar when parking and exiting the locomotives.[5]

Late model Series 7 locomotives were equipped with side doors on which the outside door latch handle is mounted near floor level, with a simple drawer pull type handle at mid door level. No. E1845 and later locomotives were observed with the lower mounted door handles. No. E1882 is one observed exception, with a high mounted door handle, although this may have been the result of a door replacement.[5][6]


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.[7]

Reclassification and rebuilding[edit]

Reclassification to Class 16E[edit]

No. E1851 as Class 16E no. 16-410B, Christiana, 22 September 2006

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. Most pairs were later either disbanded, with the locomotives reverting to Class 6E1 and regaining their original numbers, or rebuilt to Class 18E.[7]

Twelve known Series 7 locomotives were part of such Class 16E pairs.[7]

  • E1790 became 16-407B.
  • E1840 and E1841 became 16-409 A and B.
  • E1846 and E1847 became 16-404 A and B.
  • E1848 and E1849 became 16-405 A and B.
  • E1850 and E1851 became 16-410 A and B.
  • E1858 and E1859 became 16-411 A and B.
  • E1870 became 16-406B.

Modification to Class 17E[edit]

No. E1826 as Class 17E, Capital Park, 28 September 2006

Class 17E locomotives were modified and reclassified from Class 6E1, Series 7, 8 and 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.[7]

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.[8]

Fourteen Series 7 locomotives are known to have been modified and reclassified to Class 17E, their numbers being E1749, E1775, E1776, E1777, E1778, E1801, E1803, E1805, E1810, E1822, E1826, E1827, E1832 and E1843.[7]

Rebuilding to Class 18E[edit]

Cab 1 of Class 18E no. 18-213, ex Class 6E1 no. E1873, Capital Park, Pretoria, 6 May 2013

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 and the driver's front and side windows were blanked off to have a toilet installed, thereby forfeiting the locomotive's bi-directional ability.[7][8]

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.[8]

Most of the Class 6E1, Series 7 locomotives which were used in this project, were rebuilt to Class 18E, Series 1 locomotives. The known numbers and renumbering details are listed in the table.[8]


All the Class 6E1, Series 7 locomotives were delivered new in the SAR Gulf Red and yellow whiskers livery. The main picture shows no. E1807 in Spoornet maroon livery, passing through Kaalfontein on 23 September 2009. Illustrated below are some of the other liveries in which Series 7 locomotives served.


  1. ^ a b c d e 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" (PDF). The UCW Partnership. Archived from the original (PDF) 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. ^ a b Operation - South African Classes 6E, 6E1, 16E, 17E and 18E
  5. ^ a b E1882 with high mounted door handle
  6. ^ E1845 with low mounted door handle
  7. ^ a b c d e f Railways of Southern Africa Locomotive Guide, 2002 Edition, (Compiled by John N. Middleton), p57, as amended by Combined Amendment List 4, January 2009
  8. ^ a b c d 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