South African Class 8F 4-8-0

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This article is about one of several different Cape Government Railways locomotive types to be designated "8th Class". For the others, see Cape Government Railways 8th Class locomotives.
CGR 8th Class 4-8-0 1904
South African Classes 8F & 8FW 4-8-0
Class 8FW 1236 (4-8-0).JPG
Class 8FW no. 1236 plinthed at De Aar, 27 May 2013
Type and origin
♠ Original locomotive, as built
Superheated, inside admission valves, Class 8FW
Power type Steam
Designer Cape Government Railways
(H.M. Beatty)
Builder North British Locomotive Company
Serial number 16161-16170
Model CGR 8th Class (4-8-0)
Build date 1904
Total produced 10
Specifications
Configuration 4-8-0 (Mastodon)
Driver 2nd coupled axle
Gauge 3 ft 6 in (1,067 mm) Cape gauge
Leading dia. 28 12 in (724 mm)
Coupled dia. 48 in (1,219 mm)
Tender wheels 33 12 in (851 mm) as built
34 in (864 mm) retyred
Wheelbase 46 ft 10 12 in (14,288 mm)
 • Engine 23 ft 3 in (7,087 mm)
 • Leading 6 ft (1,829 mm)
 • Coupled 13 ft 6 in (4,115 mm)
 • Tender 14 ft 7 in (4,445 mm)
 • Tender bogie 4 ft 7 in (1,397 mm)
Length:
 • Over couplers 54 ft 2 14 in (16,516 mm)
Height 12 ft 10 in (3,912 mm)
Frame type Bar
Axle load ♠ 11 LT 14 cwt (11,890 kg)
12 LT 11 cwt (12,750 kg)
 • Leading ♠ 12 LT 9 cwt (12,650 kg)
12 LT 15 cwt (12,950 kg)
 • Coupled ♠ 11 LT 14 cwt (11,890 kg)
 • 1st coupled 11 LT 18 cwt (12,090 kg)
 • 2nd coupled 12 LT 11 cwt (12,750 kg)
 • 3rd coupled 11 LT 19 cwt (12,140 kg)
 • 4th coupled 11 LT 18 cwt (12,090 kg)
 • Tender bogie Bogie 1: 20 LT 14 cwt (21,030 kg)
Bogie 2: 22 LT 7 cwt (22,710 kg)
 • Tender axle 11 LT 3 cwt 2 qtr (11,350 kg)
Adhesive weight ♠ 46 LT 16 cwt (47,550 kg)
48 LT 6 cwt (49,080 kg)
Loco weight ♠ 59 LT 5 cwt (60,200 kg)
61 LT 1 cwt (62,030 kg)
Tender weight 43 LT 1 cwt (43,740 kg)
Total weight ♠ 102 LT 6 cwt (103,900 kg)
104 LT 2 cwt (105,800 kg)
Tender type XF (2-axle bogies)
XC, XC1, XD, XE, XE1, XF, XF1, XF2, XJ, XM, XM1, XM2, XM3 permitted
Fuel type Coal
Fuel capacity 10 LT (10.2 t)
Water cap 3,000 imp gal (13,600 l)
Firebox type Round-top
 • Firegrate area ♠ 21.35 sq ft (1.983 m2)
21 sq ft (2.0 m2)
Boiler:
 • Pitch 7 ft 3 in (2,210 mm)
 • Diameter 5 ft (1,524 mm)
 • Tube plates ♠ 11 ft 14 in (3,359 mm)
11 ft 38 in (3,362 mm)
 • Small tubes 205: 2 in (51 mm)
115: 2 in (51 mm)
 • Large tubes 18: 5 12 in (140 mm)
Boiler pressure 180 psi (1,241 kPa)
Safety valve Ramsbottom
Heating surface ♠ 1,320.6 sq ft (122.69 m2)
1,081 sq ft (100.4 m2)
 • Tubes ♠ 1,184 sq ft (110.0 m2)
950 sq ft (88 m2)
 • Firebox ♠ 136.6 sq ft (12.69 m2)
131 sq ft (12.2 m2)
Superheater:
 • Heating area 214 sq ft (19.9 m2)
Cylinders Two
Cylinder size 18 12 in (470 mm) bore
20 in (508 mm) bore
24 in (610 mm) stroke
Valve gear Stephenson
Valve type Slide - Piston
Couplers Johnston link-and-pin
AAR knuckle (1930s)
Performance figures
Tractive effort ♠ 23,110 lbf (102.8 kN) @ 75%
27,000 lbf (120 kN) @ 75%
Career
Operators Cape Government Railways
South African Railways
Class CGR 8th Class
SAR Classes 8F & 8FW
Number in class 10
Numbers CGR 829-838
SAR 1234-1243
Delivered 1904
First run 1904
Withdrawn 1972
The leading coupled axle had flangeless wheels

The South African Railways Class 8F 4-8-0 of 1904 was a steam locomotive from the pre-Union era in the Cape of Good Hope.

In 1904, the Cape Government Railways placed its final batch of ten 8th Class 4-8-0 Mastodon type steam locomotives in service. In 1912, when they were assimilated into the South African Railways, they were renumbered and designated Class 8F.[1][2][3]

Manufacture[edit]

Evolution[edit]

H.M. Beatty

The first 8th Class locomotive of the Cape Government Railways (CGR) was a 2-8-0 Consolidation type designed by H.M. Beatty, the CGR’s Chief Locomotive Superintendent from 1896 to 1910. It was later to become the Class 8X on the South African Railways (SAR). While these first Schenectady- and ALCO-built 2-8-0 locomotives were being subjected to exhaustive testing on all types of traffic and under varying conditions, some trouble was experienced with the leading two-wheeled pony truck. When designs were prepared at Salt River for a later order for more locomotives, the pony truck was replaced with a four-wheeled bogie.[1]

Builders[edit]

Orders for the last 8th Class locomotives for the CGR were placed with the North British Locomotive Company (NBL) in 1903. The ten locomotives were built and delivered in 1904, numbered in the range from 829 to 838 and allocated to the Western System of the CGR.[1][4]

Type XF tender plate

These ten locomotives were the final batch of CGR 8th Class locomotives to be built with a 4-8-0 Mastodon type wheel arrangement.[1][2]

They were delivered with Type XF tenders with a coal capacity of 10 long tons (10.2 tonnes), a water capacity of 3,000 imperial gallons (14,000 litres) and a maximum axle load of 11 long tons 3 hundredweight 2 quarters (11,350 kilograms).[5][6]

Class 8 sub-classes[edit]

When the Union of South Africa was established on 31 May 1910, the three Colonial government railways (CGR, Natal Government Railways and Central South African Railways) were united under a single administration to control and administer the railways, ports and harbours of the Union. Even though the South African Railways and Harbours came into existence in 1910, the actual classification and renumbering of all the rolling stock of the three constituent railways was only implemented with effect from 1 January 1912.[3][7]

In 1912, these ten locomotives were renumbered in the range from 1234 to 1243 and designated Class 8F.[8]

These locomotives, together with the rest of the CGR’s 8th Class 2-8-0 Consolidations and 4-8-0 Mastodons and the Classes 8-L1 to 8-L3 4-8-0 Mastodon locomotives from the Central South African Railways (CSAR), were grouped into ten different sub-classes by the SAR. The 4-8-0 locomotives were designated SAR Classes 8 and 8A to 8F and the 2-8-0 locomotives were designated Classes 8X to 8Z.[5][6]

Modification[edit]

Class 8FW 1242 (4-8-0).JPG

During A.G. Watson’s term as Chief Mechanical Engineer of the SAR from 1929 to 1936, many of the Classes 8 to 8F locomotives were equipped with superheated boilers, larger bore cylinders and either inside or outside admission piston valves. The outside admission valve locomotives had their cylinder bore increased from 18 12 to 19 inches (470 to 483 millimetres) and retained their existing SAR classifications, while the inside admission valve locomotives had their cylinder bore increased to 20 inches (508 millimetres) and were reclassified by having a "W" suffix added to their existing SAR classifications.[2][5][6]

Of the Class 8F locomotives, numbers 1236, 1242 and 1243 were equipped with superheated boilers, 20 inches (508 millimetres) bore cylinders and inside admission piston valves, and reclassified to Class 8FW.[5][6]

Service[edit]

In SAR service, the 4-8-0 Class 8 family of locomotives worked on every system in the country and, in the 1920s, became the mainstay of motive power on many branchlines. Their final days were spent in shunting service. They were all withdrawn from service by 1972.[2]

Illustration[edit]

References[edit]

  1. ^ a b c d Holland, D.F. (1971). Steam Locomotives of the South African Railways, Volume 1: 1859-1910 (1st ed.). Newton Abbott, Devon: David & Charles. p. 67. ISBN 978-0-7153-5382-0. 
  2. ^ a b c d Paxton, Leith; Bourne, David (1985). Locomotives of the South African Railways (1st ed.). Cape Town: Struik. pp. 48–49. ISBN 0869772112. 
  3. ^ a b Classification of S.A.R. Engines with Renumbering Lists, issued by the Chief Mechanical Engineer’s Office, Pretoria, January 1912, pp. 9, 12, 15, 43 (Reprinted in April 1987 by SATS Museum, R.3125-6/9/11-1000)
  4. ^ North British Locomotive Company works list, compiled by Austrian locomotive historian Bernhard Schmeiser
  5. ^ a b c d 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. pp. VIII, 45.
  6. ^ a b c d 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. VIII, 6a-7a, 20-21, 25, 45.
  7. ^ The South African Railways - Historical Survey. Editor George Hart, Publisher Bill Hart, Sponsored by Dorbyl Ltd., Published c. 1978, p. 25.
  8. ^ Holland, D.F. (1972). Steam Locomotives of the South African Railways, Volume 2: 1910-1955 (1st ed.). Newton Abbott, Devon: David & Charles. p. 140. ISBN 978-0-7153-5427-8.