South African Class GDA 2-6-2+2-6-2

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South African Class GDA 2-6-2+2-6-2
Class GDA 2255 (2-6-2+2-6-2).jpg
No. 2255, Stanger Depot, 8 September 1966
Type and origin
Power type Steam
Designer Beyer, Peacock and Company
Builder Linke-Hofmann Werke AG
Serial number 3115-3119
Model Class GDA
Build date 1929
Total produced 5
Specifications
Configuration 2-6-2+2-6-2 (Double Prairie)
Driver 3rd & 4th coupled axles
Gauge 3 ft 6 in (1,067 mm) Cape gauge
Leading dia. 28 12 in (724 mm)
Coupled dia. 46 in (1,168 mm)
Trailing dia. 28 12 in (724 mm)
Wheelbase 58 ft 4 in (17,780 mm)
 • Engine 18 ft 9 in (5,715 mm) each
 • Coupled 8 ft 6 in (2,591 mm) each
Pivot centres 30 ft 6 in (9,296 mm)
Length:
 • Over couplers 65 ft 11 in (20,091 mm)
Height 12 ft 10 14 in (3,918 mm)
Frame type Bar
Axle load 13 LT 14 cwt (13,920 kg)
 • Leading 12 LT 1 cwt (12,240 kg) front
11 LT 7 cwt (11,530 kg) rear
 • 1st coupled 13 LT 1 cwt (13,260 kg)
 • 2nd coupled 13 LT 8 cwt (13,620 kg)
 • 3rd coupled 13 LT 8 cwt (13,620 kg)
 • 4th coupled 13 LT 14 cwt (13,920 kg)
 • 5th coupled 13 LT 13 cwt (13,870 kg)
 • 6th coupled 12 LT 7 cwt (12,550 kg)
 • Trailing 8 LT 7 cwt (8,484 kg) front
8 LT 11 cwt (8,687 kg) rear
Adhesive weight 79 LT 11 cwt (80,830 kg)
Loco weight 119 LT 17 cwt (121,800 kg)
Fuel type Coal
Fuel capacity 5 LT (5.1 t)
Water cap 2,300 imp gal (10,500 l) front
1,500 imp gal (6,820 l) rear
Firebox type Round-top
 • Firegrate area 40 sq ft (3.7 m2)
Boiler:
 • Pitch 7 ft 9 14 in (2,369 mm)
 • Diameter 5 ft 11 34 in (1,822 mm)
 • Tube plates 10 ft 7 78 in (3,248 mm)
 • Small tubes 193: 2 in (51 mm)
 • Large tubes 32: 5 12 in (140 mm)
Boiler pressure 180 psi (1,241 kPa)
Safety valve Pop
Heating surface 1,750 sq ft (163 m2)
 • Tubes 1,569 sq ft (145.8 m2)
 • Firebox 181 sq ft (16.8 m2)
Superheater:
 • Heating area 370 sq ft (34 m2)
Cylinders Four
Cylinder size 15 in (381 mm) bore
24 in (610 mm) stroke
Valve gear Walschaerts
Valve type Piston
Couplers AAR knuckle
Performance figures
Tractive effort 31,690 lbf (141.0 kN) @ 75%
Career
Operators South African Railways
Class Class GDA
Number in class 5
Numbers 2255-2259
Delivered 1929
First run 1929
Withdrawn c. 1972

The South African Railways Class GDA 2-6-2+2-6-2 of 1929 was an articulated steam locomotive.

In December 1929, the South African Railways placed five Class GDA Garratt articulated locomotives with a 2-6-2+2-6-2 Double Prairie type wheel arrangement in branch line service on the Natal North Coast line.[1][2][3]

Manufacturer[edit]

The Class GDA 2-6-2+2-6-2 Double Prairie type Garratt locomotive was built to the same specifications and was for all intents and purposes identical to the Class GD in its main dimensions. They were ordered from Linke-Hofmann Werke AG in Breslau, Germany in 1929 and numbered 2255 to 2259 upon delivery in December of that same year.[1][2][3][4][5]

Characteristics[edit]

The locomotive had the same tractive effort as the Class GD, was also superheated and also had Walschaerts valve gear to actuate its piston valves. The main differences were the use of bar frames instead of plate frames, differently shaped coal and water bunkers, and a round-topped firebox instead of a Belpaire firebox.[1][2][3][4][5][6]

Service[edit]

The five locomotives were placed in service working out of Cape Town where they were to join the Class GD on the Overberg branch across Sir Lowry's Pass to Caledon and Bredasdorp, but they were found to be not satisfactory in service and ended up being staged on a siding near the Cape Town sheds for a considerable time. When a question was raised in the local press, enquiring the reason why these brand new locomotives were not being used, they were first moved to a less conspicuous location and shortly afterwards transferred to Natal.[1]

The Natal shops managed to get the locomotives to perform satisfactorily and they were placed in branch line service on the North Coast line in Natal, working around Stanger. This line contains long gradients of 1 in 40 (2½%) and severe curvature with curves of 300 feet (91 metres) radius. Some locomotives later ended up working on the Port Alfred branch. In 1970 a pair was sent to Port Elizabeth where they worked local goods trains until they were all withdrawn by 1972.[1][2][3]

SAR locomotive policy[edit]

During the term of office of Colonel F.R. Collins DSO as SAR Chief Mechanical Engineer from 1922 to 1929 articulated locomotives were in great favour in South Africa, to the extent that the Railway Board of the day instructed that non-articulated engines should only be ordered in exceptional circumstances. His retirement in 1929 brought about a change in policy, however, and there would be an interval of nearly a decade before another articulated Cape gauge Garratt would be acquired.[7]

Preservation[edit]

Two locomotives were "preserved". No. 2257 was plinthed at Grahamstown Station. After the branch line via Grahamstown to Port Alfred fell into disuse, however, an apathetic local government allowed Grahamstown's historic station buildings and especially the plinthed locomotive to be vandalised to an eyesore state by 2013. Another engine, no. 2259, was staged at the South African National Railway And Steam Museum in Krugersdorp.

Illustration[edit]

References[edit]

  1. ^ a b c d e Holland, D.F. (1972). Steam Locomotives of the South African Railways, Volume 2: 1910-1955 (1st ed.). Newton Abbott, Devon: David & Charles. pp. 61–62. ISBN 978-0-7153-5427-8. 
  2. ^ a b c d Espitalier, T.J.; Day, W.A.J. (1946). The Locomotive in South Africa - A Brief History of Railway Development. Chapter VII - South African Railways (Continued). South African Railways and Harbours Magazine, February 1946. p. 134.
  3. ^ a b c d Paxton, Leith; Bourne, David (1985). Locomotives of the South African Railways (1st ed.). Cape Town: Struik. pp. 90–91. ISBN 0869772112. 
  4. ^ a b South African Railways & Harbours/Suid Afrikaanse Spoorweë en Hawens (15 Aug 1941). Locomotive Diagram Book/Lokomotiefdiagramboek, 3'6" Gauge/Spoorwydte. SAR/SAS Mechanical Department/Werktuigkundige Dept. Drawing Office/Tekenkantoor, Pretoria. p. 31.
  5. ^ a b South African Railways & Harbours/Suid Afrikaanse Spoorweë en Hawens (15 Aug 1941). Locomotive Diagram Book/Lokomotiefdiagramboek, 2'0" & 3'6" Gauge/Spoorwydte, Steam Locomotives/Stoomlokomotiewe. SAR/SAS Mechanical Department/Werktuigkundige Dept. Drawing Office/Tekenkantoor, Pretoria. p. 31.
  6. ^ Hamilton, Gavin N., The Garratt Locomotive - Garratt Locomotives from Other Builders, retrieved 10 November 2012 
  7. ^ Espitalier, T.J.; Day, W.A.J. (1946). The Locomotive in South Africa - A Brief History of Railway Development. Chapter VII - South African Railways (Continued). South African Railways and Harbours Magazine, January 1946. p. 13.