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

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.

See also

References

  1. 1.0 1.1 Beyer, Peacock and Company production list, excluding Garratts, Customer List V1 04.08.02
  2. 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. 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. 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. 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. 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.
  7. The South African Railways - Historical Survey. Editor George Hart, Publisher Bill Hart, Sponsored by Dorbyl Ltd., Published c. 1978, p. 25.