South African Class 31-000

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South African Class 31-000
ex South African Class 1-DE
SAR Class 31-000 31-028 R.JPG
No. 31-028 (D727) at Bellville Depot, 31 October 2010
Type and origin
Power type Diesel-electric
Designer General Electric
Builder General Electric
Serial number 33507-33551 [1]
Model GE U12B
Build date 1958
Total produced 45
AAR wheel arr. B-B
UIC classification Bo'Bo'
Gauge 3 ft 6 in (1,067 mm) Cape gauge
Wheel diameter 915 mm (36.0 in)
Wheelbase 2.438 m (8 ft 0 in) per bogie
10.118 m (33 ft 2.3 in) total
Length 15.150 m (49 ft 8.5 in)
Width 2.780 m (9 ft 1.4 in)
Height 3.916 m (12 ft 10.2 in)
Axle load 18,900 kg (41,700 lb)
Locomotive weight 74,000 kg (163,000 lb) average
76,600 kg (168,900 lb) permissible
Fuel type Fuel oil
Fuel capacity 3,000 litres (660 imp gal; 790 US gal)
Prime mover Cooper-Bessemer FVBL-8
Engine RPM range 400 rpm idle
535 rpm high idle
1,000 rpm maximum
Engine type 4 stroke diesel
Aspiration Cooper-Bessemer ET13 turbocharger
Generator DC 10 pole GE 5GT-581C3
Traction motors Four GE 5GE-761A4 DC 4 pole
* 600A rating 1 hour
* 590A rating continuous
at 16 km/h (9.9 mph)
Cylinders V8
Valve lead 1
Transmission 94/17 gear ratio (???)
Multiple working 3 maximum
Performance figures
Maximum speed 90 km/h (56 mph)
Power output 985 kW (1,321 hp) starting
895 kW (1,200 hp) continuous
Tractive effort 181 kN (41,000 lbf) starting
145 kN (33,000 lbf) continuous
at 18 km/h (11 mph)
Factor of
25% starting, 20% continuous
Locomotive brake 6-SLAV-1 with vigilance control
Not equipped with dynamic brakes
65% ratio at 345 kPa (50.0 psi) brake cylinder pressure
Train brakes 700 litres (180 US gal) main reservoir
Compressor capacity at high idle: 0.039 m3/s (1.4 cu ft/s)
Exhauster capacity at high idle: 0.155 m3/s (5.5 cu ft/s)
Operator(s) South African Railways
Class Class 31-000
Number in class 45
Number(s) 31-001 to 31-045 (D700-D744)
Delivered June to July 1958
First run 1958 [2]

The South African Class 31-000 of 1958 is a South African diesel-electric locomotive from the South African Railways era.

In June and July 1958 the South African Railways placed forty-five Class 1-DE General Electric type U12B diesel-electric locomotives in service. They were later reclassified to Class 31-000 and renumbered.[2]


The South African Class 31-000 type GE U12B diesel-electric locomotive was designed for the South African Railways (SAR) and built by General Electric in 1958 and imported. They were the first diesel-electric road locomotives to enter SAR service in quantity.[2][3]

Reclassification & renumbering[edit]

Upon delivery, they were classified as Class 1-DE and numbered in the range from D700 to D744 in the electric locomotive number range. When the SAR adopted a new classification and numbering system for electric and diesel-powered locomotives circa 1960, they were reclassified to Class 31-000 and renumbered in the range from 31-001 to 31-045.[2][3]


The Class 31-000 is a high short hood locomotive. While the short hood end is usually considered as the front end, the cab is equipped with dual station controls to make it fully bidirectional.[2]


They were placed in service working out of Johannesburg to Kroonstad in the Free State and to Volksrust on the mainline to Natal. By the 1980s they were relegated to shunting and pickup service on the Reef and at some other major centres.[3]

Of the original forty-five locomotives, forty survived into the Spoornet era in the 1990s. Now retired from Spoornet service, some still see service in private hands. Three of them, numbers 31-001 (D700), 31-005 (D704) and 31-038 (D737), were acquired by Sheltam for use at Rand Uranium near Randfontein and at Welkom. The first two were converted to low short hood locomotives and were still in service in 2014, while the third was used for spare parts.[1][4]

Another private rail operator, RRL Grindrod, owns no. 31-009 (D708) as its no. RB-201 which is employed at Welkom.[4]

Works numbers[edit]

The Class 31-000 builder’s works numbers, renumbering and disposition are listed in the table.[1]

Liveries illustrated[edit]

Some of the liveries that were applied to Class 31-000 locomotives are illustrated below.

See also[edit]


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  1. ^ a b c 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. 38, 45. 
  2. ^ a b c d e South African Railways Index and Diagrams Electric and Diesel Locomotives, 610 mm and 1065 mm Gauges, Ref LXD 14/1/100/20, 28 January 1975, as amended
  3. ^ a b c Paxton, Leith; Bourne, David (1985). Locomotives of the South African Railways (1st ed.). Cape Town: Struik. pp. 137–138. ISBN 0869772112. 
  4. ^ a b SAR-L Yahoogroup message no. 47981 of 17 October 2014