South African Class GA 2-6-0+0-6-2

Class GA no. 1649, renumbered to no. 2140, c. 1921

Type and origin
Power type	Steam
Designer	Beyer, Peacock and Company
Builder	Beyer, Peacock and Company
Serial number	5941
Model	Class GA
Build date	1920
Total produced	1

Specifications
Configuration	2-6-0+0-6-2 (Double Mogul)
Driver	3rd & 4th coupled axles
Gauge	3 ft 6 in (1,067 mm) Cape gauge
Leading dia.	30 in (762 mm)
Coupled dia.	48 in (1,219 mm)
Wheelbase	58 ft 7 in (17,856 mm)
• Engine	16 ft 2 in (4,928 mm) each
• Coupled	9 ft (2,743 mm) each
Pivot centres	33 ft 3 in (10,135 mm)
Length:
• Over couplers	65 ft 6 in (19,964 mm)
Height	12 ft 10 in (3,912 mm)
Frame type	Plate
Axle load	17 LT 16 cwt (18,090 kg)
• Leading	14 LT 9 cwt (14,680 kg) front 14 LT 4 cwt (14,430 kg) rear
• 1st coupled	17 LT 3 cwt (17,430 kg)
• 2nd coupled	17 LT 14 cwt (17,980 kg)
• 3rd coupled	17 LT 7 cwt (17,630 kg)
• 4th coupled	17 LT 9 cwt (17,730 kg)
• 5th coupled	17 LT 16 cwt (18,090 kg)
• 6th coupled	17 LT 5 cwt (17,530 kg)
Adhesive weight	104 LT 14 cwt (106,400 kg)
Loco weight	133 LT 17 cwt (136,000 kg)
Fuel type	Coal
Fuel capacity	9 LT (9.1 t)
Water cap	3,350 imp gal (15,200 l) front 1,250 imp gal (5,680 l) rear
Firebox type	Belpaire
• Firegrate area	51.8 sq ft (4.81 m²)
Boiler:
• Pitch	7 ft 9 in (2,362 mm)
• Diameter	6 ft 9 in (2,057 mm)
• Tube plates	11 ft 8 ¹⁄₄ in (3,562 mm)
• Small tubes	279: 2 in (51 mm)
• Large tubes	40: 5 ¹⁄₄ in (133 mm)
Boiler pressure	180 psi (1,241 kPa)
Safety valve	Ramsbottom
Heating surface	2,554.5 sq ft (237.32 m²)
• Tubes	2,342.2 sq ft (217.60 m²)
• Firebox	211.3 sq ft (19.63 m²)
Superheater:
• Heating area	526.5 sq ft (48.91 m²)
Cylinders	Four
Cylinder size	18 in (457 mm) bore 26 in (660 mm) stroke
Valve gear	Walschaerts
Valve type	Piston
Couplers	Bell link-and-pin

Performance figures
Tractive effort	47,390 lbf (210.8 kN) @ 75%

Career
Operators	South African Railways
Class	Class GA
Number in class	1
Numbers	1649, renumbered 2140
Delivered	1921
First run	1921
Withdrawn	1938

The South African Railways Class GA 2-6-0+0-6-2 of 1921 was an articulated steam locomotive.

In February 1921, the South African Railways placed a single experimental Class GA Garratt articulated steam locomotive with a 2-6-0+0-6-2 Double Mogul type wheel arrangement in service. It was the first Cape gauge Garratt to enter service in South Africa.^[1]^[2]^[3]

The Garratt solution

A powerful steam locomotive is problematic on Cape gauge light-rail single-line track. Train lengths were limited on such lines because, due to restrictions on axle loading, conventional locomotives had been enlarged to the limit of their possible power. Alternative solutions would either be double-heading longer trains or rebuilding and re-aligning large parts of the lines to accommodate heavier locomotives. Either method was expensive, especially across the type of mountainous terrain that was encountered inland from all South Africa's major ports. In such conditions, the Garratt design had distinct advantages.^[4]

Manufacturer

The Class GA experimental mainline articulated locomotive was one of altogether five Garratt locomotives that had been ordered by the South African Railways (SAR) from Beyer, Peacock and Company (BP) in 1914. The rest consisted of the first of the eventual seven Class GB 2-6-2+2-6-2 branchline locomotives and three narrow gauge Class NG G11 2-6-0+0-6-2 locomotives. Production was disrupted by the First World War, 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.^[1]^[2]^[3]^[5]

The single Class GA was numbered 1649, but the engine number was later changed to 2140. The locomotive was erected in the Durban shops and placed in service in February 1921. At the time, it was 40 long tons (40.6 tonnes) heavier than any Garratt engine constructed previously and, of all Garratts in service woldwide, the locomotive with the highest tractive effort.^[1]^[2]^[3]

Characteristics

The superheated Class GA had a commodious cab and had plate frames, with a copper Belpaire firebox. The piston valves were actuated by Walschaerts valve gear, driven from the coupled wheels furthest from the respective cylinders, and controlled by steam reversing gear, which was fitted under the boiler barrel between the cradle frame plates. The bissel trucks at the extremities of the locomotive were fitted with Cartazzi axle box control to allow the axles sideways play, since the truck itself did not pivot, but was compensated with the adjacent pair of coupled wheels.^[1]^[2]^[3]^[6]

The locomotive had valves to allow the steam supply to either engine unit to be shut off, if necessary. Exhaust steam from the cylinders of each engine unit was led to the smokebox by separate pipes. The ball joints which gave flexibility to the steam and exhaust pipes, were located immediately under and concentric with the pivot centres and were served by forced lubrication from Wakefield mechanical lubricators. Two 8 feet (2,438 millimetres) lubricators, one on each engine unit, supplied one feed to each cylinder and each steam chest, two to the ball joints and two to the tail-end extensions of the piston rods. The oil pipes which fed the steam chests and cylinders, were fitted with anti-carbonisers. The locomotive was fitted with two Gresham and Craven no. 12 self-acting feedwater injectors and had steam sanding gear, applied to the front and rear of both engine units.^[2]

Comparative trials

The Class GA, which had apparently been designed as a direct competitor to the Class MH 2-6-6-2 Mallet, was placed in trial service on the Natal mainline. It closely matched the Mallet in terms of tractive effort, boiler capacity, grate area and axle loading, which made it a locomotive of equal power but with 46 long tons (46.7 tonnes) less weight. Tests were carried out with varying loads on various sections of the line, while comparative tests were carried out with the Class MH Mallets.^[1]^[2]^[3]^[7]

During the trials, the locomotive gave some trouble due to broken plate frames on the engine units and it was also found that the absence of trailing carrying wheels on the engine units was a disadvantage, since it led to excessive flange wear on the coupled wheels. As a result, no. 2140 remained the only representative of its Class. All subsequent Garratt models of the SAR were equipped with trailing Bissel trucks.^[1]^[2]^[3]

The Garratt took greater loads than the Mallet and its running times were better, while its coal and water consumption were lower. With the Garratt's superiority established, no further Mallet locomotives were ordered by the SAR. During the remaining years of the South African steam traction era, whenever the use of an articulated locomotive was desirable for flexibility, reduced axle loading and high tractive force, the Garratt type was chosen.^[1]^[2]^[3]

Service

The locomotive worked across Van Reenen's Pass between Ladysmith and Harrismith for most of the rest of its service life. It was withdrawn from service in 1938 because of a cracked frame and scrapped. The boiler was retained and reconditioned as a spare boiler for Class GE locomotives.^[2]^[3]

References

1 2 3 4 5 6 7 Holland, D.F. (1972). Steam Locomotives of the South African Railways, Volume 2: 1910-1955 (1st ed.). Newton Abbott, Devon: David & Charles. p. 41. ISBN 978-0-7153-5427-8.
1 2 3 4 5 6 7 8 9 Espitalier, T.J.; Day, W.A.J. (1945). The Locomotive in South Africa - A Brief History of Railway Development. Chapter VII - South African Railways (Continued). South African Railways and Harbours Magazine, November 1945. pp. 866-867.
1 2 3 4 5 6 7 8 Paxton, Leith; Bourne, David (1985). Locomotives of the South African Railways (1st ed.). Cape Town: Struik. pp. 88–89. ISBN 0869772112.
↑ Beyer, Peacock Garratt Locomotives
↑ Hamilton, Gavin N., The Garratt Locomotive - Garratt Locomotives produced by Beyer, Peacock, retrieved 10 November 2012
↑ Hendrie (10 December 1921). "Engine Power on the S.A.R.". South African Mining and Engineering Journal. XXXII (1576): 529.
↑ Durrant, A E (1989). Twilight of South African Steam (1st ed.). Newton Abbott, London: David & Charles. pp. 25, 123. ISBN 0715386387.

Wikimedia Commons has media related to South African Class GA (2-6-0+0-6-2).

Locomotives of South Africa

Steam

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4' 8½" gauge	Cape 0-4-0T Blackie Cape 0-4-2 Cape 2-4-0T CGR 0-4-0ST Aid Natal 0-4-0ST Durban Natal 0-4-0WT Natal Natal 4-4-0T Perseverance

3' 6" gauge Tank engines	CGR 0-4-0ST 1873 CGR 0-4-0ST 1874 CGR 0-4-0ST 1881 Coffee Pot CGR 0-6-0ST 1902 CGR 0-6-0T 1876 Back-to-Back CGR 2-6-0ST 1900 CGR 2-6-0ST 1902 CGR 1st Class 0-4-0ST 1875 CGR 1st Class 0-4-0ST 1876 CGR 1st Class 2-6-0ST 1876 CGR 1st Class 4-4-0T 1875 CGR 2nd Class 4-4-0T 1882 CGR 3rd Class 2-6-0T CGR Railmotor CSAR Class C CSAR Class E CSAR Rack CSAR Railmotor DSWA Eight-Coupled Tank 2-8-0T Durban's Congella Durban's Edward Innes Durban's John Milne Durban's Sir Albert Port Elizabeth Harbour 0-4-0ST Kowie Railway 0-6-0T Kowie Railway 4-4-0T Metropolitan & Suburban 4-6-2T NGR 2-6-0T Durban & Pietermaritzburg NGR Class I 2-6-2T NGR Class K 0-4-0ST NGR Class K 0-6-0ST NGR Class K 2-6-0T NZASM 10 Tonner NZASM 13 Tonner NZASM 14 Tonner NZASM 18 Tonner NZASM 19 Tonner NZASM 32 Tonner NZASM 40 Tonner PPR 26 Tonner PPR 35 Tonner Portuguese SAR 0-4-0ST 1903 SAR 0-4-0T no. 69 SAR Class A SAR Class B SAR Class C SAR Class C1 SAR Class C2 SAR Class D SAR Class E SAR Class F SAR Class G SAR Class H SAR Class H1 SAR Class H2 SAR Class J SAR Class K SAR Clayton

3' 6" gauge Tender engines	CGR 1st Class 2-6-0 1876 Beyer, Peacock CGR 1st Class 2-6-0 1876 Kitson CGR 1st Class 2-6-0 1879 CGR 1st Class 2-6-0 1891 CGR 1st Class 4-4-0 1879 CGR 1st Class 4-4-0TT 1881 CGR 2nd Class 2-6-2TT 1875 CGR 3rd Class 4-4-0 1883 CGR 3rd Class 4-4-0 1884 CGR 3rd Class 4-4-0 1889 CGR 3rd Class 4-4-0 1898 CGR 3rd Class 4-4-0 1901 CGR 3rd Class 4-4-0 1903 CGR 4th Class 4-4-2 CGR 4th Class 4-6-0TT 1880 CGR 4th Class 4-6-0TT 1882 CGR 4th Class 4-6-0TT Joy 1882 CGR 4th Class 4-6-0TT 1884 CGR 5th Class 4-6-0 1890 CGR 5th Class 4-6-0 1891 DSWA Eight-Coupled Tender 2-8-0 NGR Havelock NGR Class I SAR Class Exp 1 SAR Class Exp 2 SAR Class Exp 3 SAR Class Exp 4 SAR Class Exp 5 SAR Class Exp 6 SAR Class S SAR Class S1 SAR Class S2 SAR Class 1 SAR Class 1A SAR Class 1B SAR Class 2 SAR Class 2C SAR Class 3 SAR Class 3A SAR Class 3B SAR Class 4 SAR Class 4A SAR Class 5 SAR Class 5A SAR Class 5B SAR Class 6 SAR Class 6A SAR Class 6B SAR Class 6C SAR Class 6D SAR Class 6E SAR Class 6F SAR Class 6G SAR Class 6H SAR Class 6J SAR Class 6K SAR Class 6L SAR Class 6Y SAR Class 6Z SAR Class 7 SAR Class 7A SAR Class 7B SAR Class 7C SAR Class 7D SAR Class 7E SAR Class 7F SAR Class 8 SAR Class 8A SAR Class 8B SAR Class 8C SAR Class 8D SAR Class 8E SAR Class 8F SAR Class 8R SAR Class 8X SAR Class 8Y SAR Class 8Z SAR Class 9 SAR Class 10 SAR Class 10A SAR Class 10B SAR Class 10C SAR Class 10D SAR Class 11 SAR Class 12 SAR Class 12A SAR Class 12B SAR Class 13 SAR Class 14 SAR Class 14A SAR Class 14B SAR Class 14C 1st SAR Class 14C 2nd SAR Class 14C 3rd SAR Class 14C 4th SAR Class 15 SAR Class 15A SAR Class 15B SAR Class 15C SAR Class 15CA SAR Class 15E SAR Class 15F SAR Class 16 SAR Class 16A SAR Class 16B SAR Class 16C SAR Class 16D SAR Class 16DA SAR Class 16E SAR Class 17 SAR Class 18 SAR Class 19 SAR Class 19A SAR Class 19B SAR Class 19C SAR Class 19D SAR Class 20 SAR Class 21 SAR Class 23 SAR Class 24 SAR Class 25 SAR Class 25NC SAR Class 26 SAR Katanga

3' 6" gauge Articulated engines	CGR Fairlie CGR Kitson-Meyer SAR Class FC SAR Class FD SAR Class GA SAR Class GB SAR Class GC SAR Class GCA SAR Class GD SAR Class GDA SAR Class GE SAR Class GEA SAR Class GF SAR Class GG SAR Class GH SAR Class GK SAR Class GL SAR Class GM SAR Class GMA SAR Class GO SAR Class HF SAR Class KM SAR Class MA SAR Class MB SAR Class MC SAR Class MC1 SAR Class MD SAR Class ME SAR Class MF SAR Class MG SAR Class MH SAR Class MJ SAR Class MJ1 SAR Class U

2' 6" gauge	Cape Copper 0-6-0T 1871 Cape Copper Britannia Cape Copper Caledonia Cape Copper Clara Cape Copper Condenser Cape Copper Scotia Namaqua Copper Pioneer

2' & 600mm gauges	ACR Class NG-G16A CGR NG 0-6-0T CGR NG 4-6-2T CGR Type A 2-6-4T CGR Type C 0-4-0T DSWA Class Ha DSWA Class Hb DSWA Class Hc DSWA Class Hd DSWA Jung DSWA Zwillinge NGR Class N 4-6-2T SAR Dutton SAR NG 0-4-0T 1899 SAR Class NG1 SAR Class NG2 SAR Class NG3 SAR Class NG4 SAR Class NG5 SAR Class NG6 SAR Class NG7 SAR Class NG8 SAR Class NG9 SAR Class NG10 SAR Class NG-G11 SAR Class NG-G12 SAR Class NG-G13 SAR Class NG-G14 SAR Class NG15 SAR Class NG-G16

Electric

Amcoal Class E38

Gas-electric

Gas-electric

Diesel

3' 6" gauge Diesel-electric	PRASA Class Afro 4000 SAR Class DS SAR Class DS1 SAR Class 31-000 SAR Class 32-000 SAR Class 32-200 SAR Class 33-000 SAR Class 33-200 SAR Class 33-400 SAR Class 34-000 SAR Class 34-200 SAR Class 34-400 SAR Class 34-500 SAR Class 34-600 SAR Class 34-800 SAR Class 34-900 SAR Class 35-000 SAR Class 35-200 SAR Class 35-400 SAR Class 35-600 SAR Class 36-000 SAR Class 36-200 SAR Class 37-000 Spoornet Class 39-000 TFR Class 35-800 TFR Class 39-200 TFR Class 43-000 TFR Class 44-000

2' gauge Diesel-electric	SAR Class 91-000

3' 6" gauge Diesel-hydraulic	SAR Class 61-000

3' 6" gauge Electro-diesel	Spoornet Class 38-000

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