South African Class 7E3, Series 1

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South African Class 7E3, Series 1
Class 7E3 Series 1 E7216.JPG
No. E7216 at Pyramid South, Pretoria, 14 May 2013
Specifications
Power type Electric
Designer Hitachi
Builder Dorbyl
Model Hitachi 7E3
Build date 1983-1984
Total produced 60
UIC classification Co-Co
Gauge 3 ft 6 in (1,067 mm) Cape gauge
Bogies 4.06 m (13 ft 3.8 in) wheelbase
Wheel diameter 1,220 mm (48 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 brake Rheostatic [2][3]
Train brakes Air & Vacuum
Career
Railroad(s) South African Railways
Spoornet
Transnet Freight Rail
Class Class 7E3 [3]
Power class 25 kV AC
Number in class 44
Number E7216-E7259
Delivered 1983-1984
First run 1983

The South African Class 7E3, Series 1 of 1983 is a South African electric locomotive from the South African Railways era.

Between 1983 and 1984 the South African Railways placed sixty Class 7E3, Series 1 electric locomotives with a Co-Co wheel arrangement in mainline service. Circa 2000 sixteen of these dual cab locomotives were rebuilt to single cab locomotives and reclassified to Class 7E4.[1][3]

Manufacturer[edit]

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

Like Union Carriage and Wagon (UCW), Dorbyl did not allocate builder’s numbers to the locomotives it built for the SAR, but used the SAR running numbers for their record keeping.[1]

Features[edit]

Builders’ plate on no. E7252

On the Class 7E3, Series 1, control of traction and rheostatic braking 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]

Unlike the Classes 7E and 7E2 Series 1 and 2 where thyristors are used, these locomotives feature silicon-diode rectifiers.[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 number 1 end. Series 1 and Series 2 locomotives are visually indistinguishable from each other, but the two sides of the locomotives are sufficiently different in appearance that a pair of them coupled at the same end appears at first glance to be two different locomotive types. The roof access ladder side is smooth, while the other side has several large grilles.[1]

Modifications and reclassifications[edit]

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

Class 7E4[edit]

Circa 2000 seventeen Class 7E3 locomotives, sixteen Series 1, numbers 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 the conversion from double cab to single cab, since the cab space was required for some of the new equipment that was installed. These modified single cab locomotives were reclassified to Class 7E4.[3]

Class 7E5[edit]

The conversions to Class 7E4 were costly, however, and it was decided to modify further Class 7E3 locomotives to a lesser extent, gaining almost the same benefits at a lower cost since they remained as double cab locomotives. In total about fifty locomotives of both series were upgraded in this manner. These were reclassified to Class 7E5, although externally they were still identical to the Class 7E3.[3]

Class 7E6[edit]

Following some systems failures on the upgraded Class 7E5 locomotives, a further variation in the modifications was applied to the remaining Class 7E3 locomotives that had not yet been upgraded. These locomotives were then reclassified to Class 7E6. Eventually all the Class 7E5 locomotives were also modified once again to meet the Class 7E6 specifications.[3]

Revert to Class 7E3[edit]

Since by October 2007 all these locomotives were fully upgraded and, apart from the single cab Class 7E4 conversions, once again identical, they reverted to their original Class 7E3 classifications. Although numbers E7216 to E7259 are all officially Class 7E3, Series 1 once again, many of these forty-four locomotives still bore markings to identify them as either Class 7E5 or Class 7E6. The single cab locomotives, however, remained classified as Class 7E4.[3]

Service[edit]

Since 1978, 25 kV AC was introduced on all new mainline 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 7E3, Series 1 locomotives all served on the 25 kV AC Coalink line from Ermelo via Vryheid to the Richards Bay Coal Terminal until sufficient numbers of the Class 19E were available by about 2011 to allow some to be re-allocated to Pyramid South north of Pretoria.[2][3]

Liveries illustrated[edit]

The main picture shows number E7216 in Spoornet blue livery with solid numbers, still inscribed "7E6". The difference between the sides of the locomotive and some other liveries that were applied to the Class 7E3, Series 1 are illustrated below.

See also[edit]

References[edit]

  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. ^ 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 g h i 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. ^ Jane's Train Recognition Guide