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
Type and origin
Power typeElectric
Designer Hitachi
Builder Dorbyl
ModelHitachi 7E3
Build date1983-1984
Total produced60
RebuilderTranswerk
Rebuild date2000-2003
Number rebuilt16 to Class 7E4
Specifications
Configuration:
​
 •  AAR C-C
 •  UIC Co'Co'
 • Commonwealth Co-Co
Gauge 3 ft 6 in (1,067 mm) Cape gauge
Wheel diameter1,220 mm (48.03 in)
Wheelbase 13,460 mm (44 ft 1+7⁄8 in)
 •  Bogie 4,060 mm (13 ft 3+7⁄8 in)
Pivot centres10,200 mm (33 ft 5+5⁄8 in)
Panto shoes12,075 mm (39 ft 7+3⁄8 in)
Length:
​
 • Over couplers18,430 mm (60 ft 5+5⁄8 in)
 • Body17,480 mm (57 ft 4+1⁄4 in)
Width2,906 mm (9 ft 6+3⁄8 in)
Height:
​
 • Pantograph4,180 mm (13 ft 8+5⁄8 in)
 • Body height3,941 mm (12 ft 11+1⁄8 in)
Axle load 21,420 kg (47,220 lb)
Adhesive weight 123,500 kg (272,300 lb)
Loco weight123,500 kg (272,300 lb)
Electric system/s 25 kV AC 50 Hz catenary
Current pickup(s) Pantographs
Traction motors Six HS-1054-GR
 • Rating 1 hour525 kW (704 hp)
 • Continuous500 kW (670 hp)
Gear ratio16:94
Loco brake Air & Rheostatic
Train brakes Air & Vacuum
Couplers AAR knuckle
Performance figures
Maximum speed100 km/h (62 mph)
Power output:
​
 • 1 hour3,150 kW (4,220 hp)
 • Continuous3,000 kW (4,000 hp)
Tractive effort:
​
 • Starting450 kN (100,000 lbf)
 • 1 hour319 kN (72,000 lbf)
 • Continuous300 kN (67,000 lbf)
Career
OperatorsSouth African Railways
Spoornet
Transnet Freight Rail
Class Class 7E3
Number in class44
NumbersE7216-E7259
Delivered1983-1984
First run1983

The South African Railways Class 7E3, Series 1 of 1983 is an electric locomotive.

Contents

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. Beginning in 2001, sixteen of these dual cab locomotives were rebuilt to single cab locomotives and reclassified to Class 7E4. [1] [2] [3]

Manufacturer

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 in 1983 and 1984, numbered in the range from E7216 to E7275. [1] [4]

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 unit numbers for their record keeping. [1]

Features

Appearance

Builders' plate, no. E7252 Plate Hitachi 7E3 (E7252).JPG
Builders’ plate, no. E7252

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. 1 end. Series 1 and Series 2 loco­mo­tives are visually indistinguishable from each other, but the two sides of both series are sufficiently different in appearance that a pair of them coupled at the same ends 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]

Pantographs

The locomotive's pantograph placement is unusual in not being equidistant from the locomotive ends. The contact shoe centre of the no. 1 end pantograph is 6,155 millimetres (20 feet 2.3 inches) from the longitudinal centre of the locomotive, while that of the no. 2 end pantograph is 5,920 millimetres (19 feet 5.1 inches) from the longitudinal centre. [1]

Brakes

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. [4]

Unlike the Classes 7E and 7E2 Series 1 and 2 where thyristors are used, these locomotives use silicon-diode rectifiers. [5]

Bogies

To reduce flange and rail wear, the bogies of the Class 7E3 have a shorter wheelbase than the Class 7E1, 4,060 millimetres (13 feet 3.8 inches) instead of 4,400 millimetres (14 feet 5.2 inches). [1] [4]

Like the Class 7E1, the Class 7E3 was built with sophisticated traction linkages on the 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. [4]

Reclassifications

In the period from the early 1990s until 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. [2]

Class 7E4

From 2001, seventeen Class 7E3 locomotives, sixteen Series 1, numbers E7260 to E7275, and one Series 2, no. E7276, underwent significant modifications. This included the installation of Hitachi micro-processor controls with improved rheostatic brakes, auxiliary inverters designed and built by Fuji, and the conversion from double cab to single cab since the no. 2 end cab space was required for some of the new equipment. These modified single-cab locomotives were reclassified to Class 7E4. [2] [3]

Class 7E5

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. [2]

Class 7E6

Following some systems failures on the upgraded Class 7E5 locomotives, a further variation in the modifications was applied to the remaining Class 7E3 locomotives which had not yet been upgraded. These units were then reclassified to Class 7E6. Eventually all the Class 7E5 locomotives were also modified once again to meet the Class 7E6 specifications. [2]

Revert to Class 7E3

By October 2007 all these locomotives were fully upgraded and standardised in respect of their rheostat flat topping and EPROM software. Since, apart from the single cab Class 7E4 conversions, they were once again all identical, those which had been reclassified to Classes 7E5 and 7E6 reverted to their original Class 7E3 classifications. Although numbers E7216 to E7259 are all officially designated Class 7E3, Series 1 once again, many of these 44 locomotives still bore markings for several years to identify them as either Class 7E5 or Class 7E6. The single cab locomotives remained classified as Class 7E4. [2] [3]

Service

Since 1978, 25 kV AC was introduced on all new mainline electrification projects bar one, the 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. They remained there until sufficient numbers of the new Class 19E were available by about 2011 to allow some of the Class 7E3 to be re-allocated to Pyramid South, north of Pretoria. [2] [4]

Liveries

All the Class 7E3, Series 1 locomotives were delivered in the SAR red oxide livery with signal red buffer beams and cowcatchers, yellow whiskers and with the number plates on the sides mounted on three-stripe yellow wings. In the 1990s some of them were repainted in the Spoornet orange livery with a yellow and blue chevron pattern on the buffer beams and cowcatchers. In the late 1990s many were repainted in the Spoornet blue livery with either solid or outline numbers on the long hood sides. [6]

JANUARY 2022

Caption text
Header textHeader textHeader textHeader textHeader textHeader text
7216
7217
7218
7219
7220
7221
7222
7223
7224
7225
7226
7227
7228
7229
7230
7231
7232
7233
7234
7235
7236
7237
7238
7239
7240
7241
7242
7243
7244
7245
7246
7247
7248
7250
7251
7252
7253
7254
7255
7256
7257
7258
7259

Illustration

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References

  1. 1 2 3 4 5 6 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. 1 2 3 4 5 6 7 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.
  3. 1 2 3 Information received from several Transnet employees
  4. 1 2 3 4 5 Paxton, Leith; Bourne, David (1985). Locomotives of the South African Railways (1st ed.). Cape Town: Struik. pp. 129–131. ISBN   0869772112.
  5. ↑ Jane's Train Recognition Guide
  6. ↑ Soul of A Railway, System 7, Western Transvaal, based in Johannesburg, Part 9. South-Eastwards as far as Volksrust (2nd part) by Les Pivnic. Caption 4. (Accessed on 11 April 2017)
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