South African Class 5B 4-6-2
South African Class 5B 4-6-2 & South African Class 5BR 4-6-2 ex CGR Karoo Class 4-6-2 | |
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Class 5B no. 723 plinthed at Strand, 12 April 1970 | |
Type and origin | |
Power type | Steam |
Designer | Cape Government Railways |
Builder | Beyer, Peacock and Company |
Order number | 9124 |
Serial number | 4567-4570 [1] |
Model | CGR Karoo Class |
Build date | 1904 [1][2] |
Total produced | 4 |
Specifications | |
Configuration | 4-6-2 "Pacific" |
Gauge | 3 ft 6 in (1,067 mm) Cape gauge |
Leading wheel diameter | 28.5 in (724 mm) |
Driver diameter | 60 in (1,520 mm) |
Trailing wheel diameter | 33 in (838 mm) |
Wheelbase |
Total: 48 ft 10.375 in (14.894 m) Engine: 5 ft 9 in (1.753 m) bogie 10 ft 5 in (3.175 m) coupled 28 ft 3 in (8.611 m) total Tender: 10 ft 6 in (3.200 m) |
Length |
57 ft 7.75 in (17.570 m) as built 59 ft (17.983 m) reboilered |
Height |
12 ft 10 in (3.912 m) as built 12 ft 11 in (3.937 m) reboilered |
Frame | Bar frame |
Axle load |
14.9 long tons (15.1 t) on 2nd & 3rd drivers as built 14.6 long tons (14.8 t) on 2nd driver reboilered |
Weight on drivers |
43.85 long tons (44.6 t) as built 43.4 long tons (44.1 t) reboilered |
Locomotive weight |
66.85 long tons (67.9 t) as built 68.95 long tons (70.1 t) reboilered |
Tender weight |
34,470 lb (15.6 t) empty 34 long tons (34.5 t) w/o |
Locomotive and tender combined weight |
100.85 long tons (102.5 t) as built 102.95 long tons (104.6 t) reboilered |
Tender type |
YE1 - YB, YC, YE, YE1 permitted * 3 axle tender * 37 in (940 mm) wheels * Length 21 ft 4.375 in (6.512 m) |
Fuel type | Coal |
Fuel capacity | 6 long tons (6.1 t) |
Water capacity | 2,825 imp gal (12,840 l) |
Boiler |
As Built: 4 ft 9 in (1.448 m) inside diameter 15 ft (4.572 m) inside length 7 ft 1 in (2.159 m) pitch Reboilered: 5 ft (1.524 m) inside diameter 17 ft 9 in (5.410 m) inside length, steel firebox 17 ft 8.625 in (5.401 m) inside length, copper firebox 8 ft (2.438 m) pitch |
Boiler pressure | 180 psi (1,240 kPa) |
Firegrate area |
27 sq ft (2.508 m2) as built 36 sq ft (3.345 m2) reboilered |
Heating surface: – Tubes |
As Built: 77 tubes 2 in (50.8 mm) diameter 16 tubes 5.5 in (140 mm) diameter 993 sq ft (92.253 m2) Reboilered: 76 tubes 2.5 in (63.5 mm) diameter 24 tubes 5.5 in (140 mm) diameter 1,497 sq ft (139.076 m2) |
– Firebox |
110 sq ft (10.219 m2) as built 123 sq ft (11.427 m2) reboilered |
– Total |
1,103 sq ft (102.472 m2) as built 1,620 sq ft (150.503 m2) reboilered |
Superheater type | Not installed as built |
Superheater area |
324 sq ft (30.101 m2) modified 5B 366 sq ft (34.003 m2) Class 5BR |
Cylinders | Two |
Cylinder size |
18.5 in (470 mm) bore 26 in (660 mm) stroke |
Valve gear | Stephenson |
Performance figures | |
Tractive effort | 22,240 lbf (99 kN) at 75% pressure |
Career | |
Operator(s) |
Cape Government Railways South African Railways |
Class |
CGR Karoo Class SAR Class 5B, Class 5BR [3] |
Number in class | 4 |
Number(s) |
CGR 905-908 SAR 723-726 [2][4][5] |
Nicknames | Karoo |
Delivered | 1904 |
First run | 1904 |
Withdrawn | 1969 |
The South African Class 5B 4-6-2 of 1904 is a South African steam locomotive from the pre-Union era in the Cape Colony.
In 1904 the Cape Government Railways placed four Karoo Class 4-6-2 Pacific type passenger steam locomotives in service. In 1912, when they were assimilated into the South African Railways, they were renumbered and classified as Class 5B.[2][4][6]
Manufacturer
Following on the success of the first two Karoo Class locomotives of the Cape Government Railways (CGR), a further four were ordered from Beyer, Peacock and Company in 1904 and delivered in that same year. They were modified slightly in view of the experience gained with the original two Karoo locomotives.[2][3]
They were numbered in the range from 905 to 908 and, like the previous two locomotives, they were also not allocated class numbers by the CGR. Instead they were also known as the Karoo Class, from the region of the Western System where they were designed to work.[2]
Class 5 sub-classes
The Union of South Africa was established on 31 May 1910, in terms of the South Africa Act, enacted by the Parliament of the United Kingdom. One of the clauses in the Act required that the three Colonial Government railways, the CGR, the Natal Government Railways and the Central South African Railways, also be united under one single administration to control and administer the railways, ports and harbours of the Union.[7]
While the South African Railways (SAR) came into existence in 1910, the actual classification and renumbering of all the rolling stock of the three constituent railways required careful planning and was only implemented with effect from 1 January 1912.[4]
In 1912 these four locomotives were renumbered in the range from 723 to 726 and reclassified to Class 5B on the SAR. The rest of the CGR’s Karoo Class locomotives were grouped into two more sub-classes by the SAR.[3][4][5]
Modifications
Watson Standard boilers
In the 1930s many serving locomotives were reboilered with a standard boiler type designed by then Chief Mechanical Engineer (CME) A.G. Watson as part of his standardisation policy. Such Watson Standard reboilered locomotives were reclassified by adding an "R" suffix to their classification.[3][6]
Only one of the Class 5B locomotives, number 725, was eventually reboilered with a Watson Standard no. 1 boiler and reclassified to Class 5BR.[3][6]
Piston valves
Watson also equipped the Class 5B and Class 5BR with superheating and piston valve cylinders. The Class 5BR was equipped with superheating at the time that it was reboilered with a Watson Standard boiler and reclassified, but the remaining Class 5B locomotives were not reclassified after this modification.[3][6]
At the same time their running boards were raised clear of the coupled wheels. This modification made the as-built wheel fairings on the running boards unnecessary and resulted in a locomotive with a North American rather than a British appearance.
Service
In service the Class 5B locomotives performed excellently. CGR Chief Locomotive Superintendent H.M. Beatty’s annual report for 1905 stated that they collectively ran 171,000 miles (275,000 kilometres) without a failure of any description.[2]
They spent a large part of their working lives in the Karoo working between Beaufort West and De Aar, until they were displaced by larger locomotives and assigned to the Paardeneiland shed in Cape Town. Some remained in service around Cape Town for many years and became familiar sights on the Strand and Stellenbosch suburban trains, until the last locomotive of this Class was withdrawn by 1969.[6]
Upon withdrawal no. 723 was plinthed at Strand station. It was subsequently first moved to De Aar, where it was observed in April 1980 as part of the well-known and well-maintained collection of preserved locomotives. No. 723 as well as most of the other locomotives in the De Aar collection were subsequently relocated to Millsite near Krugersdorp.
Modifications illustrated
The main picture shows no. 723 while it was still plinthed at Strand station, with running boards that had been raised clear of the coupled wheels.
The first of the following pictures shows the Class 5B in the CGR's green livery, with polished brass dome covers and with its original low running boards with wheel fairings or splashers, depicted here on a colourised CGR post card that also shows the CGR's crest. The second shows it in the later all black livery of the SAR and after being equipped with superheating, piston valve cylinders, raised running boards and raised tender sides to increase the coal capacity.
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CGR Karoo Class no. 905, SAR Class 5B no. 723
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Class 5B no. 724, ex CGR Karoo Class no. 906, circa 1930
See also
- List of South African locomotive classes
- South African Class 5 4-6-2
- South African Class 5A 4-6-2
- South African Class Exp 1 4-6-2
- South African locomotive history
- Tender locomotive numbering and classification
- The 4-6-2 "Pacific"
- Watson Standard boilers
References
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- ↑ 1.0 1.1 Beyer, Peacock and Company production list, excluding Garratts, Customer List V1 04.08.02
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 Holland, D.F. (1971). Steam Locomotives of the South African Railways, Volume 1: 1859-1910 (1st ed.). Newton Abbott, Devon: David & Charles. pp. 71–72. ISBN 978-0-7153-5382-0.
- ↑ 3.0 3.1 3.2 3.3 3.4 3.5 South African Railways and Harbours Locomotive Diagram Book, 2’0” & 3’6” Gauge Steam Locomotives, 15 August 1941, as amended
- ↑ 4.0 4.1 4.2 4.3 Classification of S.A.R. Engines with Renumbering Lists, issued by the Chief Mechanical Engineer’s Office, Pretoria, January 1912, pp. 8, 12, 14, 34 (Reprinted in April 1987 by SATS Museum, R.3125-6/9/11-1000)
- ↑ 5.0 5.1 Holland, D.F. (1972). Steam Locomotives of the South African Railways, Volume 2: 1910-1955 (1st ed.). Newton Abbott, Devon: David & Charles. p. 137. ISBN 978-0-7153-5427-8.
- ↑ 6.0 6.1 6.2 6.3 6.4 Paxton, Leith; Bourne, David (1985). Locomotives of the South African Railways (1st ed.). Cape Town: Struik. p. 39. ISBN 0869772112.
- ↑ The South African Railways - Historical Survey. Editor George Hart, Publisher Bill Hart, Sponsored by Dorbyl Ltd., Published c. 1978, p. 25.