South African Class S 0-8-0

South African Class S 0-8-0

No. 355 at Millsite, 8 April 1966
Type and origin
Power type Steam
Designer South African Railways
(Col F.R. Collins DSO)
Builder Henschel and Son
Serial number 21071-21084
Model Class S
Build date 1928
Total produced 14
Specifications
Configuration 0-8-0 (Eight-coupled)
Driver 3rd coupled axle
Gauge 3 ft 6 in (1,067 mm) Cape gauge
Coupled dia. 48 in (1,219 mm)
Tender wheels 34 in (864 mm)
Wheelbase 48 ft 2 116 in (14,683 mm)
  Engine 14 ft 9 in (4,496 mm)
  Coupled 14 ft 9 in (4,496 mm)
  Tender 20 ft 5 in (6,223 mm)
  Tender bogie 6 ft 2 in (1,880 mm)
Length:
  Over couplers 64 ft 10 516 in (19,769 mm)
Height 13 ft (3,962 mm)
Frame type Bar
Axle load 18 LT (18,290 kg)
  Coupled 18 LT (18,290 kg)
  Tender bogie Bogie 1: 29 LT 4 cwt (29,670 kg)
Bogie 2: 31 LT 19 cwt (32,460 kg)
  Tender axle 15 LT 19 cwt 2 qtr (16,230 kg)
Adhesive weight 72 LT (73,160 kg)
Loco weight 72 LT (73,160 kg)
Tender weight 61 LT 3 cwt (62,130 kg)
Total weight 133 LT 3 cwt (135,300 kg)
Tender type GT (2-axle bogies)
Fuel type Coal
Fuel capacity 8 LT (8.1 t)
Water cap 6,000 imp gal (27,300 l)
Firebox type Round-top
  Firegrate area 41 sq ft (3.8 m2)
Boiler:
  Pitch 8 ft 6 in (2,591 mm)
  Diameter 5 ft 6 18 in (1,680 mm)
  Tube plates 14 ft (4,267 mm)
  Small tubes 135: 2 in (51 mm)
  Large tubes 28: tubes 5 12 in (140 mm)
Boiler pressure 170 psi (1,172 kPa)
Safety valve Pop
Heating surface 1,699 sq ft (157.8 m2)
  Tubes 1,554 sq ft (144.4 m2)
  Arch tubes 20 sq ft (1.9 m2)
  Firebox 125 sq ft (11.6 m2)
Superheater:
  Heating area 450 sq ft (42 m2)
Cylinders Two
Cylinder size 23 14 in (591 mm) bore
25 in (635 mm) stroke
Valve gear Walschaerts
Valve type Piston
Couplers AAR knuckle
Performance figures
Tractive effort 35,890 lbf (159.6 kN) @ 75%
Career
Operators South African Railways
Class Class S
Number in class 14
Numbers 360-373
Delivered 1929
First run 1929
Withdrawn 1976
The 3rd coupled axle had flangeless wheels

The South African Railways Class S 0-8-0 of 1929 was a steam locomotive.

In 1929, the South African Railways placed fourteen purpose-built Class S steam shunting locomotives with a 0-8-0 wheel arrangement in service.[1][2][3]

Background

Throughout the history of railways in South Africa, shunting was traditionally performed by downgraded mainline locomotives. Considering the enormous amount of shunting performed, the number of dedicated shunting locomotives on the South African Railways (SAR) roster in the steam era was remarkably low, amounting to only 151 locomotives on a railway whose steam stock at one stage reached a maximum of nearly 2,800 locomotives.[4]

When it did eventually introduce purpose-built shunting locomotives, the SAR preferred to adhere to the American practice of using tender locomotives for shunting, rather than the European practice of using tank engines.[4]

Manufacturer

Col F.R. Collins DSO

In spite of the conversion of Class A tank locomotives to Class 17 tender shunting locomotives, increasing rail traffic throughout the country and particularly on the Witwatersrand in the 1920s, still made it necessary to use heavy mainline locomotives for shunting work. Specifications for the Class S 0-8-0 tender type steam shunting locomotive were therefore prepared by Colonel F.R. Collins, Chief Mechanical Engineer of the SAR.[1][3]

In 1928, fourteen locomotives were built to the SAR specifications by Henschel and Son in Germany. They were delivered in 1929 and numbered in the range from 360 to 373. Since they were designed to operate at low speeds in tightly curved shunting yards, there was no need for the leading or trailing wheels which are necessary on mainline locomotives to improve high speed stability. In addition, it was desirable to have as large a proportion of the engine weight as possible carried on the coupled wheels to obtain the maximum adhesion.[1][2][3][5][6][7]

Characteristics

To improve the crew's rearward vision, the top sides of the tender's coal bunker were set inwards and the water tank top was rounded. The locomotives were superheated, were built on bar frames and used Walschaerts valve gear.[1][2][3]

When they were first introduced, their boiler pressure was set at 216 pounds per square inch (1,489 kilopascals), giving a tractive effort of 45,500 pounds-force (202 kilonewtons) at 75% boiler pressure. Since they tended to be slippery, however, the operating boiler pressure was reduced to 170 pounds per square inch (1,172 kilopascals) in 1933, resulting in a corresponding reduction in tractive effort to 35,890 pounds-force (159.6 kilonewtons) at 75% boiler pressure.[1][2][6][7]

Service

South African Railways

The Class S was initially placed in service in the Orange Free State and Natal, but they were soon transferred to Transvaal, where they spent most of the rest of their working lives, rendering good service in yards at several centres. The Class ended up being mainly a Western Transvaal locomotive, stationed at Germiston, Kaserne, Krugersdorp, Springs and at Beaconsfield in Kimberley, with a solitary locomotive at Volksrust.[3][4]

Industrial

They were withdrawn from SAR service in 1976. Four were sold to Dunn's in 1977, from where they eventually ended up at several locations.[3][4]

Illustration

References

  1. 1 2 3 4 5 Holland, D.F. (1972). Steam Locomotives of the South African Railways, Volume 2: 1910-1955 (1st ed.). Newton Abbott, Devon: David & Charles. pp. 63–65. ISBN 978-0-7153-5427-8.
  2. 1 2 3 4 Espitalier, T.J.; Day, W.A.J. (1946). The Locomotive in South Africa - A Brief History of Railway Development. Chapter VII - South African Railways (Continued). South African Railways and Harbours Magazine, Jun 1946. p. 455.
  3. 1 2 3 4 5 6 Paxton, Leith; Bourne, David (1985). Locomotives of the South African Railways (1st ed.). Cape Town: Struik. p. 80. ISBN 0869772112.
  4. 1 2 3 4 Durrant, A E (1989). Twilight of South African Steam (1st ed.). Newton Abbott, London: David & Charles. p. 120. ISBN 0715386387.
  5. Henschel-Lieferliste (Henschel & Son works list), compiled by Dietmar Stresow
  6. 1 2 South African Railways & Harbours/Suid Afrikaanse Spoorweë en Hawens (15 Aug 1941). Locomotive Diagram Book/Lokomotiefdiagramboek, 3'6" Gauge/Spoorwydte. SAR/SAS Mechanical Department/Werktuigkundige Dept. Drawing Office/Tekenkantoor, Pretoria. p. 46.
  7. 1 2 South African Railways & Harbours/Suid Afrikaanse Spoorweë en Hawens (15 Aug 1941). Locomotive Diagram Book/Lokomotiefdiagramboek, 2'0" & 3'6" Gauge/Spoorwydte, Steam Locomotives/Stoomlokomotiewe. SAR/SAS Mechanical Department/Werktuigkundige Dept. Drawing Office/Tekenkantoor, Pretoria. pp. 6a-7a, 37, 46.
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