South African Class 7E4

South African Class 7E4
(ex South African Class 7E3 Series 1 & 2)
E7275 at Vryheid, KwaZulu-Natal, 16 August 2007
Power type Electric
Designer Hitachi
Builder Dorbyl
Model Hitachi 7E3
Build date 1983-1984 (7E3 Series 1)
1984-1985 (7E3 Series 2)
Total produced 85
Rebuilder Transwerk
Rebuild date Circa 2000
Number rebuilt 17
UIC classification Co-Co
Gauge 3 ft 6 in (1,067 mm) Cape gauge
Bogies 4.060 m (13 ft 3.8 in) wheelbase
Wheel diameter 1,220 mm (48.0 in)
Wheelbase 13.46 m (44 ft 1.9 in)
Length 18.43 m (60 ft 5.6 in)
Width 2.906 m (9 ft 6.4 in)
Height 4.18 m (13 ft 8.6 in) pantographs down
Axle load 21,420 kg (21.1 long tons)
Locomotive weight 123,500 kg (121.5 long tons)
Current collection
method		 Pantographs
Traction motors Six HS 1054 GR
Transmission 16/94 Gear ratio
Top speed 100 km/h (62 mph)
Power output Per motor:
525 kW (704 hp) 1 hour
500 kW (670 hp) continuous
Total:
3,150 kW (4,220 hp) 1 hour
3,000 kW (4,000 hp) continuous
Tractive effort 450 kN (100,000 lbf) starting
319 kN (72,000 lbf) 1 hour
300 kN (67,000 lbf) continuous[1]
Locomotive brakes Rheostatic[2][3]
Train brakes Air & Vacuum
Career South African Railways
Spoornet
Transnet Freight Rail
Class Class 7E4[3]
Power class 25 kV AC
Number in class 17
Number E7260-E7276
Delivered Circa 2000
First run Circa 2000

In 1983 and 1984 the South African Railways placed sixty Class 7E3, Series 1 electric locomotives with a Co-Co wheel arrangement in main line service. These were followed by another twenty-five Class 7E3, Series 2 locomotives in 1984 and 1985. Circa 2000 seventeen of these dual cab locomotives were rebuilt to single cab locomotives and reclassified to Class 7E4.[3]

Contents

Manufacturers

The Class 7E3 25 kV AC electric locomotives were designed for the South African Railways (SAR) by Hitachi and built in South Africa by Dorbyl, who also supplied the mechanical components. Sixty Series 1 locomotives were delivered by Dorbyl in 1983 and 1984, numbered E7216 to E7275, and twenty-five Series 2 locomotives in 1984 and 1985, numbered E7276 to E7300.[1][2]

Like Union Carriage and Wagon, Dorbyl did not allocate builder’s numbers to the locomotives it built for the SAR. While the usual practice by most other locomotive builders was to allocate builder’s numbers or works numbers to record the locomotives built by them, Dorbyl simply used the SAR running numbers for their record keeping.[1]

Modification and reclassification

Control of traction and rheostatic braking on these locomotives is by stepless solid-state electronics. The electrical equipment was designed for high power factor operation, obtained by the switching in of power-factor correction capacitors.[2]

In the period from the early 1990s until about 2007 various modifications to improve downhill braking capacity were done to the Coalink line Hitachi designed locomotives. The first set of upgrades was done on the fifty Class 7E1 locomotives.[3]

Circa 2000 seventeen Class 7E3 locomotives, sixteen Series 1, numbered E7260 to E7275, and one Series 2, number E7276, underwent significant modifications. This included the installation of Hitachi micro-processor controls with improved rheostatic brakes and conversion from double cab to single cab, since the cab space was required for some of the new equipment that was installed. These single cab locomotives were reclassified to Class 7E4.[3]

Service

Since 1978, 25 kV AC was introduced on all new main line electrification projects bar one, the one exception being the Orex iron ore line from Sishen to Saldanha, where 50 kV AC is used. The Class 7E4 locomotives all serve on the 25 kV AC Coalink line from Ermelo via Vryheid to the Richards Bay Coal Terminal.[2][3]

Liveries

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 "SPOORNET" in Spoornet’s orange era, and blue with the Spoornet logo but without "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 the Blue Train was relegated to the very bottom of the railway’s business priority list.[4][5]

While it is doubtful that the intention was to have a Class 7E4 in blue train livery for blue train hauling on the Richards Bay line, E7275 was nevertheless painted in Spoornet’s maroon era Blue Train livery after being rebuilt. The main picture shows the Class 7E4’s right side.[5]

See also

References

  1. ^ a b c 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. ^ a b c d Paxton, Leith; Bourne, David (1985). Locomotives of the South African Railways (1st ed.). Cape Town: Struik. pp. 129-131. ISBN 0869772112. 
  3. ^ a b c d e f 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, 61. 
  4. ^ E1973 with blue based on orange livery
  5. ^ a b E1951 with blue based on maroon livery