South African Class 7F 4-8-0

South African Class 7F 4-8-0
Ex New Cape Central Railway Class 7 no. 10
South African Railways Class 7F 1358
Power type Steam
Designer Cape Government Railways
Builder North British Locomotive Company
Serial number 20217-20219[1][2]
Model CGR Class 7
Build date 1913
Total produced 3
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 42.75 in (1,090 mm)
Wheelbase Total: 46 ft 6 in (14.173 m)
Engine:
5 ft 3 in (1.600 m) pilot
12 ft (3.658 m) coupled
21 ft 3.5 in (6.490 m) total
Tender:
4 ft 7 in (1.397 m) bogie
16 ft 1 in (4.902 m) total
Length 53 ft 9.125 in (16.386 m)
Height 12 ft 10 in (3.912 m)
Frame Plate frame
Axle load 9.8 long tons (10.0 t) on 1st & 3rd drivers
Weight on drivers 39 long tons (39.6 t)
Locomotive weight 49.7 long tons (50.5 t)
Tender weight 38,960 lb (17.7 t) empty
35.5 long tons (36.1 t) w/o
Locomotive & tender
combined weight		 106,232 lb (48.2 t) empty
85.2 long tons (86.6 t) w/o
Tender type ZC - ZA, ZB, ZC, ZE permitted
* 2 axle bogies
* Wheels 34 in (864 mm) dia
* Length 23 ft 9.25 in (7.245 m)
Fuel type Coal
Fuel capacity 6.5 long tons (6.6 t)
Water capacity 2,600 imp gal (12,000 l)
Boiler 4 ft 6 in (1.372 m) int dia
10 ft 9 in (3.277 m) int length
7 ft 3 in (2.210 m) pitch
Boiler pressure 180 psi (1,240 kPa)
Firegrate area 18 sq ft (1.672 m2)
Heating surface:
Tubes		 185 tubes 1.875 in (47.6 mm) dia
976 sq ft (90.673 m2)
Heating surface:
Firebox		 119 sq ft (11.055 m2)
Heating surface:
Total		 1,095 sq ft (101.729 m2)
Cylinders Two
Cylinder size 17.5 in (445 mm) bore
23 in (584 mm) stroke
Valve gear Stephenson
Tractive effort 22,240 lbf (98.9 kN) at 75% boiler pressure[3]
Factor of
adhesion		 3.928[4]
Career New Cape Central Railway
South African Railways
Class NCCR Class 7, SAR Class 7F
Number in class 3
Number NCCR 9-11, SAR 1357-1359[1]
Delivered 1913
First run 1913
Withdrawn 1940[4][5]
Disposition Retired

In 1913 the New Cape Central Railway placed three Cape Class 7 4-8-0 Mastodon steam locomotives in service. In 1925, when the New Cape Central Railway was amalgamated into the South African Railways, these three locomotives were renumbered and reclassified to Class 7F.[1][5]

Contents

New Cape Central Railway

The New Cape Central Railway (NCCR) was formed in January 1893 when it purchased all the assets of the bankrupted Cape Central Railway (CCR), who had constructed a line from Worcester via Robertson to Roodewal, now Ashton. In 1894 the NCCR began work to extend the line to Swellendam. From there it continued via Heidelberg to Riversdale, which was reached on 3 December 1903. Mosselbaai was reached in 1904.[1]

Unlike most other privately owned railways in South Africa, the NCCR prospered and was well and efficiently run. It was the last component to be added to the South African Railways (SAR) when it was amalgamated in May 1925. All the NCCR locomotives that came onto the SAR roster continued to give good service for many years.[1]

Manufacturer

These last three NCCR Class 7 locomotives were ordered from and built by the North British Locomotive Company (NBL) in 1913. While there was little difference from the original Cape Class 7 design as far as the main dimensions were concerned, these three locomotives were more modern in appearance. They were more powerful with a higher boiler pressure of 180 pounds per square inch (1,240 kilopascals) and 17.5 inches (445 millimetres) bore cylinders instead of the 17 inches (432 millimetres) bore of all but one (the Class 7C) of the earlier models.[3][4][5]

Other differences were the boiler centre line that was raised to 7 feet 3 inches (2.210 metres), a boiler diameter that was increased to 4 feet 6 inches (1.372 metres), the total boiler heating surface that was increased to 1,095 square feet (101.7 square metres), tractive effort that was increased to 22,240 pounds-force (98.9 kilonewtons) and a factor of adhesion that was reduced to 3.928.[3][4][5]

Visually obvious alterations were the smokebox saddle and the running boards. The distinctive covered smokebox saddle of earlier Class 7 locomotives was replaced with an exposed one. The running boards were no longer straight all the way through from buffer beam to cab end, but dipped ahead of the smokebox and beneath the cab, giving it the appearance of a Hendrie-designed locomotive.[1][3][4][5]

Class 7 sub-classes

When the NCCR was amalgamated into the SAR in 1925, these three Class 7 locomotives were renumbered into the SAR roster and reclassified to Class 7F.[1][5]

Other Class 7 locomotives that came onto the SAR roster from the other railways in the region in 1912, namely the Cape Government Railways (CGR), Central South African Railways (CSAR), the Natal Government Railways (NGR) and the Rhodesian Railways (RR), as well as earlier NCCR Class 7 locomotive models, were grouped into six different sub-classes by the SAR, becoming SAR Classes 7 and 7A to 7E.[3]

Service

In SAR service, the Class 7 family did duty on every system in the country. They remained in branch line service, particularly at Tarkastad and Ladysmith and also on the branch line from Touws River to Ladismith until the last ones were withdrawn in 1972. The Class 7F, however, had a shorter life span and all three locomotives were withdrawn by 1940.[4][5]

See also

References

  1. ^ a b c d e f g Holland, D.F. (1971). Steam Locomotives of the South African Railways, Volume 1: 1859-1910 (1st ed.). Newton Abbott, Devon: David & Charles. pp. 78-80. ISBN 0715353829. 
  2. ^ North British Locomotive Company works list, compiled by Austrian locomotive historian Bernhard Schmeiser
  3. ^ a b c d e South African Railways and Harbours Locomotive Diagram Book, 2’0” & 3’6” Gauge Steam Locomotives, 15 August 1941, as amended
  4. ^ a b c d e f Pattison, R.G. (1997). The Cape Seventh Class Locomotives (1st ed.). Kenilworth, Cape Town: The Railway History Group. pp. 15-16. ISBN 0958400946. 
  5. ^ a b c d e f g Paxton, Leith; Bourne, David (1985). Locomotives of the South African Railways (1st ed.). Cape Town: Struik. pp. 46-48. ISBN 0869772112.