South African Class FD 2-6-2+2-6-2

Class FD no. 2323, later renumbered no. 674

Type and origin
Power type	Steam
Designer	North British Locomotive Company
Builder	North British Locomotive Company
Serial number	23294-23297
Model	Class FD
Build date	1925
Total produced	4

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 ¹⁄₂ in (724 mm)
Coupled dia.	46 in (1,168 mm)
Trailing dia.	28 ¹⁄₂ in (724 mm)
Wheelbase	58 ft 7 in (17,856 mm)
• Engine	18 ft 7 ¹⁄₂ in (5,677 mm) each
• Coupled	8 ft 6 in (2,591 mm) each
Pivot centres	36 ft 6 in (11,125 mm)
Length:
• Over couplers	65 ft 7 ³⁄₄ in (20,009 mm)
Height	12 ft 9 ¹⁄₄ in (3,893 mm)
Frame type	Plate
Axle load	12 LT 7 cwt (12,550 kg)
• Leading	10 LT 11 cwt (10,720 kg) front 10 LT 4 cwt (10,360 kg) rear
• 1st coupled	12 LT 7 cwt (12,550 kg)
• 2nd coupled	12 LT 3 cwt (12,340 kg)
• 3rd coupled	12 LT 5 cwt (12,450 kg)
• 4th coupled	12 LT 1 cwt (12,240 kg)
• 5th coupled	12 LT (12,190 kg)
• 6th coupled	12 LT 1 cwt (12,240 kg)
• Trailing	10 LT 16 cwt (10,970 kg) front 9 LT 14 cwt (9,856 kg) rear
Adhesive weight	72 LT 17 cwt (74,020 kg)
Loco weight	114 LT 2 cwt (115,900 kg)
Fuel type	Coal
Fuel capacity	5 LT (5.1 t)
Water cap	2,500 imp gal (11,400 l) front 1,300 imp gal (5,910 l) rear
Firebox type	Belpaire
• Firegrate area	41 sq ft (3.8 m²)
Boiler:
• Pitch	7 ft 6 ¹⁄₄ in (2,292 mm)
• Diameter	6 ft (1,829 mm)
• Tube plates	10 ft 8 in (3,251 mm)
• Small tubes	190: 2 in (51 mm)
• Large tubes	32: 5 ¹⁄₂ in (140 mm)
Boiler pressure	180 psi (1,241 kPa)
Safety valve	Ramsbottom
Heating surface	1,730 sq ft (161 m²)
• Tubes	1,552 sq ft (144.2 m²)
• Firebox	178 sq ft (16.5 m²)
Superheater:
• Heating area	371 sq ft (34.5 m²)
Cylinders	Four
Cylinder size	15 in (381 mm) bore 24 in (610 mm) stroke
Valve gear	Walschaerts
Valve type	Piston
Couplers	Bell link-and-pin

Performance figures
Tractive effort	31,690 lbf (141.0 kN) @ 75%

Career
Operators	South African Railways
Class	Class FD
Number in class	4
Numbers	2320-2323, renumbered 671-674
Delivered	1926
First run	1926
Withdrawn	1949

The South African Railways Class FD 2-6-2+2-6-2 of 1926 was an articulated steam locomotive.

In 1926, the South African Railways placed four Class FD Modified Fairlie articulated steam locomotives with a 2-6-2+2-6-2 Double Prairie type wheel arrangement in service.^[1]^[2]^[3]

Manufacturer

The Class FD Modified Fairlie locomotive was designed and built for the South African Railways (SAR) by the North British Locomotive Company in 1925, to the specifications of Colonel F.R. Collins DSO, Chief Mechanical Engineer of the SAR. Four locomotives were delivered in 1926, numbered in the range from 2320 to 2323. They were later renumbered in the range from 671 to 674.^[1]^[2]^[3]^[4]

Characteristics

The Class FD was a heavier and more powerful version of the experimental Class FC, which was placed in service in 1925. It was the Modified Fairlie equivalent of the Class GD 2-6-2+2-6-2 Garratt, which was similar in both size and mechanical respects, hence the Class FD designation of these Modified Fairlies. The FA and FB classifications were never used by the SAR. The Class FD locomotives had Walschaerts valve gear, plate frames and were superheated. They proved to be powerful locomotives and good steamers, but they were less successful than their Garratt equivalent.^[1]^[2]^[3]

Shortcomings

They suffered from the same shortcomings as their Class FC predecessor. The 65 feet (19,812 millimetres) long rigid frame resulted in severe overhang on sharp curves and was also prone to metal fatigue and cracking, brought about by the long frame overhangs at the front and back, beyond the engine unit pivot centres. The overhangs, laden with the water and coal bunkers, of which about two-thirds of each extended beyond the respective pivot centres, tended to oscillate in an up-and-down motion while the locomotive was in motion.^[1]^[5]

In addition to this rather serious defect, the pivot bearings were also subject to quite rapid wear, since they carried a considerable additional load compared to those on the Garratt, as a result of the water and coal bunkers which were mounted on the main frame instead of on the engine units. This resulted in increased frequency of maintenance and, as a consequence, increased operating cost.^[1]^[3]^[5]

Service

The locomotives joined the sole Class FC in service on the Cape Midland System, working on the Grahamstown branch. They were scrapped by 1949.^[1]^[3]

Illustration

Class FD at Port Alfred, 3 September 1942

References

1 2 3 4 5 6 Holland, D.F. (1972). Steam Locomotives of the South African Railways, Volume 2: 1910-1955 (1st ed.). Newton Abbott, Devon: David & Charles. pp. 50–51. ISBN 978-0-7153-5427-8.
1 2 3 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, December 1945. p. 968.
1 2 3 4 5 Paxton, Leith; Bourne, David (1985). Locomotives of the South African Railways (1st ed.). Cape Town: Struik. p. 97. ISBN 0869772112.
↑ North British Locomotive Company works list, compiled by Austrian locomotive historian Bernhard Schmeiser
1 2 Durrant, A E (1989). Twilight of South African Steam (1st ed.). Newton Abbott, London: David & Charles. p. 31. ISBN 0715386387.

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

Locomotives of South Africa

Steam

7' ¼" gauge	East London 0-4-0VB Table Bay 0-4-0ST Table Bay 0-4-0T Table Bay 0-4-0WT

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 CGR 0-4-0ST 1881 Coffee Pot CGR 0-6-0ST CGR 0-6-0T 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 CGR 1st Class 4-4-0T CGR 2nd Class 4-4-0T CGR 3rd Class 2-6-0T CGR Railmotor CSAR Class C CSAR Class E CSAR Rack 4-6-4RT CSAR Railmotor Durban's Congella Durban's Edward Innes Durban's John Milne Durban's Sir Albert Port Elizabeth 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 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 Railmotor SAR Dock 0-4-0ST SAR Dock 0-4-0T SWA 2-8-0T

3' 6" gauge Tender engines	CGR 1st Class 2-6-0 1876 BP 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 CGR 1st Class 4-4-0TT CGR 2nd Class 2-6-2TT 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 1882 Joy CGR 4th Class 4-6-0TT 1884 CGR 5th Class 4-6-0 1890 CGR 5th Class 4-6-0 1891 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 1928 SAR Class 16DA 1930 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 SWA 2-8-0

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 John King & Miner Cape Copper Britannia Cape Copper Caledonia Cape Copper Clara Cape Copper Condenser Cape Copper Scotia Namaqua Copper Pioneer Walvis Bay 2-4-2T Hope

2' & 600mm gauges	ACR Class NG-G16A CGR NG 0-4-0T CGR NG 0-6-0T CGR NG 4-6-2T CGR Type A 2-6-4T CGR Type C 0-4-0T NGR Class N 4-6-2T SAR Dutton SAR NG 0-4-0T 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 SWA Class Ha SWA Class Hb SWA Class Hc SWA Class Hd SWA Jung SWA Zwillinge

Electric

Amcoal Class E38

Gas-electric

SAR 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 TFR Class 35-800 SAR Class 36-000 SAR Class 36-200 SAR Class 37-000 Spoornet Class 39-000 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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