South African Class GB 2-6-2+2-6-2
|South African Class GB 2-6-2+2-6-2|
Class GB no. 1650, later renumbered no. 2166, Voorbaai, 4 September 1997
|Designer||Beyer, Peacock and Company|
|Builder||Beyer, Peacock and Company|
|Serial number||5942, 6181-6186 |
|Build date||1921, 1924|
|Configuration||2-6-2+2-6-2 "Double Prairie" Garratt|
|Gauge||3 ft 6 in (1,067 mm) Cape gauge|
|28.5 in (724 mm)|
|Driver diameter||42.75 in (1,090 mm)|
|28.5 in (724 mm)|
|Wheelbase||Total: 53 ft (16.154 m)
8 ft (2.438 m) coupled
17 ft 5 in (5.309 m) total (2166)
17 ft 5.25 in (5.315 m) total (2160-2165)
|Length||59 ft 6.75 in (18.155 m)|
|Height||12 ft 3 in (3.734 m)|
|Frame||Plate frame, 26 ft 6 in (8.077 m) between pivot centres|
|Axle load||7.7 long tons (7.8 t) on 5th & 6th drivers (2166)
8 long tons (8.1 t) on 5th & 6th drivers (2160-2165)
|Weight on drivers||45.45 long tons (46.2 t) (2166)
46.45 long tons (47.2 t) (2160-2165)
|Locomotive weight||127,848 lb (58.0 t) empty
71.65 long tons (72.8 t) (2166)
76.05 long tons (77.3 t) (2160-2165)
|Fuel capacity||5 long tons (5.1 t)|
1,450 imp gal (6,600 l) front
550 imp gal (2,500 l) rear
1,520 imp gal (6,900 l) front
800 imp gal (3,600 l) rear
|Boiler||4 ft 5.875 in (1.368 m) inside diameter
10 ft 4 in (3.150 m) inside length (2166)
10 ft 4.375 in (3.159 m) inside length (2160-2165)
7 ft (2.134 m) pitch
|Boiler pressure||180 psi (1,240 kPa)|
|Firegrate area||23 sq ft (2.137 m2)|
128 tubes 1.875 in (47.6 mm) diameter
21 tubes 5.25 in (133 mm) diameter
944 sq ft (87.700 m2)
119 tubes 1.875 in (47.6 mm) diameter
21 tubes 5.25 in (133 mm) diameter
914 sq ft (84.913 m2)
|– Firebox||105 sq ft (9.755 m2) (2166)
104 sq ft (9.662 m2) (2160-2165)
|– Total||1,049 sq ft (97.455 m2) (2166)
1,018 sq ft (94.575 m2) (2160-2165)
|Superheater area||174 sq ft (16.165 m2) (2166)
203 sq ft (18.859 m2) (2160-2165)
|Cylinder size||12 in (305 mm) bore
20 in (508 mm) stroke
|Valve gear||Walschaerts |
|Tractive effort||18,190 lbf (80.9 kN) at 75% boiler pressure|
|Railroad(s)||South African Railways|
|Number in class||7|
|Number||1650, renumbered 2166, 2160-2165|
In June 1921 the South African Railways placed a single experimental Class GB Garratt articulated steam locomotive with a 2-6-2+2-6-2 wheel arrangement in service. Six more of these locomotives entered service in 1924.
The first experimental model of the eventual seven Class GB branch line Garratt articulated locomotives was one of altogether five Garratt locomotives ordered by the South African Railways (SAR) from Beyer, Peacock and Company (BP) in 1914. The rest of the order consisted of three narrow gauge Class NG G11 2-6-0+0-6-2 locomotives and a single experimental Class GA 2-6-0+0-6-2 main line locomotive. Production was disrupted by World War I, however, and BP was only able to deliver the narrow gauge locomotives in 1919 and the Cape gauge locomotives in 1921, after cessation of hostilities.
The Class GB was numbered 1650, but the running number was later changed to 2166. The locomotive was erected in the Durban shops and placed in service in June 1921. It was superheated, with a Belpaire firebox, a plate frame and Walschaerts valve gear.
The locomotive was placed in service working passenger trains on the Natal South Coast line. It proved to be a successful locomotive, having good riding qualities and flexibility on light track with poor ballasting and many curves of 300-foot (91-metre) radius.
In 1924 six more locomotives of this class were placed in service, also built by BP and numbered in the range from 2160 to 2165. A couple of them joined the first one on the South Coast line for a brief period. There were slight differences between these second batch locomotives and the original, mainly in terms of revised boiler proportions and a larger water bunker capacity. Visually, the most obvious difference was a more completely enclosed cab with side windows in place of the curved cut-outs in the cab sides of the first locomotive.
Most of the second batch of locomotives went directly to the Aliwal North to Barkley East line, famous for its reverses. The Natal locomotives were soon also relocated to work there, when the Class GC replaced them on the South Coast line later in 1924. They remained on the Barkley East branch for many years until they were withdrawn from service in 1967.
The main picture shows the retired first Class GB, number 2166, originally number 1650, at Voorbaai near Mosselbaai on 4 September 1997. Since the top of the front bunker is only about 7 feet 6 inches (2.286 metres) above the railhead, these locomotives were later equipped with a pedestal between the headlight and the water inlet to enable crew members to reach the overhead equipment when taking water.
- South African Class GA 2-6-0+0-6-2
- South African Class GC 2-6-2+2-6-2
- South African Class GCA 2-6-2+2-6-2
- South African Class GD 2-6-2+2-6-2
- South African Class GDA 2-6-2+2-6-2
- South African Class GE 2-8-2+2-8-2
- South African Class GEA 4-8-2+2-8-4
- South African Class GF 4-6-2+2-6-4
- South African Class GG 2-6-2+2-6-2
- South African Class GK 2-6-2+2-6-2
- South African Class GL 4-8-2+2-8-4
- South African Class GM 4-8-2+2-8-4
- South African Class GMA 4-8-2+2-8-4
- South African Class GO 4-8-2+2-8-4
- The 2-6-2+2-6-2 "Double Prairie"
- Articulated locomotive numbering and classification
- List of South African locomotive classes
- Holland, D.F. (1972). Steam Locomotives of the South African Railways, Volume 2: 1910-1955 (1st ed.). Newton Abbott, Devon: David & Charles. p. 41-42. ISBN 978-0-7153-5427-8.
- Hamilton, Gavin N., The Garratt Locomotive - Garratt Locomotives produced by Beyer, Peacock, retrieved 10 November 2012
- Paxton, Leith; Bourne, David (1985). Locomotives of the South African Railways (1st ed.). Cape Town: Struik. p. 89. ISBN 0869772112.
- Durrant, A E (1989). Twilight of South African Steam (1st ed.). Newton Abbott, London: David & Charles. p. 25. ISBN 0715386387.