South African Class 4E

From Wikipedia, the free encyclopedia
Jump to: navigation, search
South African Class 4E
SAR Class 4E E238.jpg
No. E238 at the Salt River Depot, Cape Town, 7 January 1966
Type and origin
Power type Electric
Designer General Electric Company
Builder North British Locomotive Company
Serial number 26859-26898
Model GEC 4E
Build date 1952-1953
Total produced 40
AAR wheel arr. 1-C+C-1
UIC class 1'C+C1'
Imperial class 1Co+Co1
Gauge 3 ft 6 in (1,067 mm) Cape gauge
Leading dia. 762 mm (30 in)
Wheel diameter 1,295 mm (51.0 in)
Wheelbase 18,390 mm (60 ft 4.0 in)
 • Bogie 6,833 mm (22 ft 5.0 in)
Pivot centres 10,795 mm (35 ft 5.0 in)
Panto shoes 14,122 mm (46 ft 4.0 in)
Wheel spacing
1-2: 2,337 mm (7 ft 8.0 in)
2-3: 2,286 mm (7 ft 6.0 in)
 • Over couplers 21,844 mm (71 ft 8.0 in)
 • Pantograph 4,140 mm (13 ft 7.0 in)
 • Body height 3,924 mm (12 ft 10.5 in)
Axle load 21,845 kg (48,160 lb)
 • Leading 13,209 kg (29,121 lb)
Adhesive weight 131,070 kilograms (288,960 lb)
Loco weight 157,488 kg (347,202 lb)
Power supply Catenary
Current collection Pantographs
Traction motors Six GEC WT580
 • Rating 1 hour 377 kW (506 hp)
 • Continuous 313 kW (420 hp)
Gear ratio 21:75
Loco brake Regenerative
Train brakes Air & Vacuum
Couplers AAR knuckle
Performance figures
Maximum speed 97 km/h (60 mph)
Power output:
 • 1 hour 2,262 kW (3,033 hp)
 • Continuous 1,878 kW (2,518 hp)
Tractive effort:
 • Starting 322 kN (72,000 lbf)
 • 1 hour 185 kN (42,000 lbf)
 • Continuous 141 kN (32,000 lbf)
Operators South African Railways
Class Class 4E
Power class 3 kV DC
Number in class 40
Numbers E219-E258
Nicknames Groen Mamba (Green Mamba)
Groot Mamba (Large Mamba)
Delivered 1952-1954
First run 1952

The South African Railways Class 4E of 1952 was an electric locomotive.

Between 1952 and 1954 the South African Railways placed forty Class 4E electric locomotives with a 1Co+Co1 wheel arrangement in service on the mainline from Cape Town across the Hex River rail pass to Touws River in the Karoo.[1]


GEC and NBL logos on the end doors

The 3 kV DC Class 4E electric locomotive was designed for the South African Railways (SAR) by the General Electric Company (GEC) and was built by the North British Locomotive Company (NBL) between 1952 and 1953. They were delivered between 1952 and 1954 and were numbered in the range from E219 to E258. The Class 4E was amongst the most powerful electric locomotives in the world at that time.[2][1][3]


NBL works plate, no. E258

These dual cab locomotives have two large grilles on one side and a passage linking the cabs on the opposite side. When observing the locomotive from the side with the grilles, the number 1 end would be to the right. Like the Classes 1E, 2E and 3E, the Class 4E has bogie mounted draft gear and an articulated inter-bogie linkage, therefore no train forces are transmitted to the locomotive body.[2]

The Class 4E has a 1Co+Co1 wheel arrangement, with an additional bissel truck (pony truck) at the outer end of each of the two three-axle powered bogies. The Classes 32-000 and 32-200 diesel-electric locomotive types also used this wheel arrangement, but the Class 4E was unique amongst South African electric locomotives in this respect.[1]


The Class 4E was specifically built for use on the mainline from Cape Town across the Hex River rail pass to Touws River, from where Class 23 and later Class 25 and Class 25NC steam locomotives took over across the stretch of unelectrified mainline to De Aar and from there to either Kimberley or Bloemfontein.[1]

SAR Class 4E E258 ID.JPG

The first locomotives to be delivered, were placed in service on the Natal mainline while electrification from Worcester to Touws River was being completed, but they eventually had to be withdrawn from Natal because the severe curvature of the Natal mainline caused their frames to crack.[4]

No. E219 was the first Class 4E locomotive to be relocated to Cape Town, where it initially ran on 1.5 kV DC power, which was still being used for the Cape Town suburban trains, until the upgrading of the lines to 3 kV DC was completed in November 1954. This restricted the locomotive's load capacity and mobility.[4]

One Class 4E locomotive even briefly served on the Western Transvaal system while being relocated from Natal to the Cape in 1957, when that system was granted permission to use no. E247 for between four and six weeks, before the locomotive was forwarded on to Cape Town.[5]

Hex River tunnel scheme[edit]

The Class 4E purchase was part of a scheme to eliminate the 1 in 40 (2½%) gradients and severe curves of the Hex River rail pass, which would entail the construction of a series of four tunnels through the Hex River Mountains. The tunnel system would have enabled a single Class 4E locomotive to haul 1,000 ton trains up the resulting 1 in 66 (1½%) gradients.[1]

The Hex River Tunnels scheme (Hexton) was initially started in 1945, but was deferred indefinitely in 1950 as a result of financial constraints. The tunnel scheme was briefly resuscitated in 1965 but was deferred once again in 1966. Work was eventually resumed in 1974 and included the remodelling of the lower section of the deviation between De Doorns and Osplaas stations as well as the construction of the short twin tunnels. This was completed in 1976, at which point financial constraints resulted in yet another postponement. Authority to proceed was only given once again in late 1979.[6][7]

When the project was resumed, the eastern portal of the longest tunnel was relocated a short distance to the southeast of the original site, while the location of the western portal remained as originally planned during the first attempt. The tunnel system was opened on 27 November 1989, by which time the Class 4Es were already retired, after having spent their entire careers double-heading trains across the Hex River rail pass.[1]


The Class 4E was delivered in an all over bottle green livery with red cowcatchers. The colour and the almost 22 metres (72 feet) length of the locomotive quickly earned it the nickname Groen Mamba (Green Mamba). This changed to Groot Mamba (Large Mamba) when the much shorter Class 5E was introduced in 1955 and nicknamed Klein Mamba (Little Mamba).[8]

Soon after they entered service, however, Hex River Valley farmers complained that the bottle green all over colour scheme made the locomotives difficult to see when they were approaching through the vineyards. Yellow lines were then added all around the locomotive to improve its visibility, with various line patterns being used before eventually settling on the V shaped whiskers on the ends which extended onto the sides, and multiple lines around the number plates on the sides. The attractive whiskers livery was eventually adopted for all the electric locomotives of the SAR.[9]

Beginning in 1960, a Gulf Red and yellow whiskers livery gradually replaced the green and yellow.[1]

Works numbers[edit]

The NBL works numbers of the Class 4E are listed in the table.[8]


The main picture shows number E238, in the bottle green and whiskers livery, at the Salt River Depot in Cape Town on 7 January 1966, while the following pictures serve to illustrate some of the other liveries used on the Class 4E during its service lifetime.


  1. ^ a b c d e f g Paxton, Leith; Bourne, David (1985). Locomotives of the South African Railways (1st ed.). Cape Town: Struik. pp. 126–127. ISBN 0869772112. 
  2. ^ a b 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
  3. ^ North British Locomotive Company works list, compiled by Austrian locomotive historian Bernhard Schmeiser
  4. ^ a b South African Railways & Harbours Photo Journal, Vol. 6, p. 15, by Les Pivnic
  5. ^ South African Railways & Harbours Photo Journal, Vol. 19, p. 9, by Les Pivnic
  6. ^ Hex River Tunnels
  7. ^ South African Construction World, July 1990, pp. 60-61
  8. ^ a b Railways of Southern Africa Locomotive Guide, 2002 Edition, (Compiled by John N. Middleton), 4E photograph, as amended by Combined Amendment List 4, January 2009
  9. ^ South African Railways & Harbours Photo Journal, Vol. 7, pp. 16-17, by Les Pivnic