South African Class 8F 4-8-0

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South African Class 8F 4-8-0
& South African Class 8FW 4-8-0
ex CGR 8th Class 4-8-0
Class 8FW 1236 (4-8-0).JPG
SAR Class 8FW no. 1236 plinthed at De Aar, 27 May 2013
Type and origin
Power type Steam
Designer Cape Government Railways
Builder North British Locomotive Company
Serial number 16161-16170 [1]
Model CGR 8th Class (4-8-0)
Build date 1903 [1][2]
Total produced 10
Specifications
Configuration 4-8-0 "Mastodon"
Gauge 3 ft 6 in (1,067 mm) Cape gauge
Leading wheel
diameter
28.5 in (724 mm)
Driver diameter 48 in (1,220 mm)
Wheelbase Total: 46 ft 10.5 in (14.288 m)
Engine:
6 ft (1.829 m) bogie
13 ft 6 in (4.115 m) coupled
23 ft 3 in (7.087 m) total
Tender:
4 ft 7 in (1.397 m) bogie
14 ft 7 in (4.445 m) total
Length 54 ft 2.25 in (16.516 m)
Height 12 ft 10 in (3.912 m)
Frame Bar frame
Axle load As built:
11.7 long tons (11.9 t) per driver
Class 8FW:
12.55 long tons (12.8 t) on 2nd driver
Weight on drivers 45.8 long tons (46.5 t) as built
48.3 long tons (49.1 t) Class 8FW
Locomotive weight 59.25 long tons (60.2 t) as built
61.05 long tons (62.0 t) Class 8FW
Tender weight 44,032 lb (20.0 t) empty
43.05 long tons (43.7 t) w/o
Locomotive and tender
combined weight
118,720 lb (53.9 t) empty
102.3 long tons (103.9 t) as built
104.1 long tons (105.8 t) Class 8FW
Tender type XF - XC, XC1, XD, XE, XE1, XF, XF1, XF2, XJ, XN, XN1, XM2, XM3 permitted
* 2 axle bogies
* 34 in (864 mm) wheels
* Length 22 ft 2.5 in (6.769 m)
Fuel type Coal
Fuel capacity 10 long tons (10.2 t)
Water capacity 3,000 imp gal (14,000 l)
Boiler As built:
5 ft (1.524 m) inside diameter
11 ft 0.25 in (3.359 m) inside length
7 ft 3 in (2.210 m) pitch
Class 8FW:
5 ft (1.524 m) inside diameter
11 ft 0.375 in (3.362 m) inside length
7 ft 3 in (2.210 m) pitch
Boiler pressure 180 psi (1,240 kPa)
Firegrate area 21 sq ft (1.951 m2)
Heating surface:
– Tubes
As built:
205 tubes 2 in (50.8 mm) diameter
1,184 sq ft (109.997 m2)
Class 8FW:
115 tubes 2 in (50.8 mm) diameter
18 tubes 5.5 in (140 mm) diameter
950 sq ft (88.258 m2)
– Firebox 137 sq ft (12.728 m2) as built
131 sq ft (12.170 m2) Class 8FW
– Total 1,321 sq ft (122.725 m2) as built
1,081 sq ft (100.428 m2) Class 8FW
Superheater type Not equipped as built
Superheater area 214 sq ft (19.881 m2) Class 8FW
Cylinders Two
Cylinder size As built: 18.5 in (470 mm) bore
Class 8FW: 20 in (508 mm) bore
All: 24 in (610 mm) stroke
Valve gear Stephenson
Performance figures
Tractive effort At 75% boiler pressure:
23,100 lbf (102.8 kN) as built
27,000 lbf (120.1 kN) Class 8FW [3]
Career
Operator(s) Cape Government Railways
South African Railways
Class CGR 8th Class
SAR Class 8F, Class 8FW
Number in class 10
Number(s) CGR 829-838
SAR 1234-1243 [4][5]
Delivered 1904
First run 1904
Withdrawn 1972 [6]

The South African Class 8F 4-8-0 of 1904 is a South African steam locomotive from the pre-Union era in the Cape Colony.

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 reclassified to Class 8F.[1][2][6]

Manufacture[edit]

Evolution[edit]

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 and, when designs were prepared at Salt River for a later order for more locomotives, it was replaced with a four-wheeled bogie.[2]

Builders[edit]

Orders were placed with the North British Locomotive Company (NBL) in 1903. The ten locomotives were delivered in 1904, numbered in the range from 829 to 838 and allocated to the Cape Western System of the CGR.[1][2]

These ten locomotives were the final batch of CGR 8th Class locomotives to be built with a 4-8-0 Mastodon type wheel arrangement. In spite of the differences in wheel arrangement, the CGR’s 8th Class 2-8-0 Consolidations and 8th Class 4-8-0 Mastodons were all grouped together into one single Class.[2][6]

Class 8 sub-classes[edit]

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. While the 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][7]

In 1912 these ten locomotives were renumbered in the range from 1234 to 1243 and reclassified to Class 8F.[5]

These locomotives, together with the rest of the CGR’s 8th Class 2-8-0 Consolidations and 8th Class 4-8-0 Mastodons, plus the Class 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 became SAR Classes 8 and 8A to 8F and the 2-8-0 locomotives became Classes 8X to 8Z.[3]

Modification[edit]

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

During A.G. Watson’s term as the Chief Mechanical Engineer (CME) of the SAR from 1929 to 1936, many of the Class 8 to Class 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 18.5 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.[3][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 were reclassified to Class 8FW.[3]

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 they became the mainstay of motive power on many branchlines. Their final days were spent in shunting service and by 1972 they were all withdrawn.[6]

See also[edit]

References[edit]

  1. ^ a b c d North British Locomotive Company works list, compiled by Austrian locomotive historian Bernhard Schmeiser
  2. ^ a b c d e 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. 
  3. ^ a b c d South African Railways and Harbours Locomotive Diagram Book, 2’0” & 3’6” Gauge Steam Locomotives, 15 August 1941, as amended
  4. ^ 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)
  5. ^ a b 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. 
  6. ^ a b c d e Paxton, Leith; Bourne, David (1985). Locomotives of the South African Railways (1st ed.). Cape Town: Struik. pp. 48–49. ISBN 0869772112. 
  7. ^ The South African Railways - Historical Survey. Editor George Hart, Publisher Bill Hart, Sponsored by Dorbyl Ltd., Published c. 1978, p. 25.