South African Class 7C 4-8-0

This article is about one of several different Cape Government Railways locomotive types to be designated "7th Class". For other CGR 7th Class locomotives, see Cape Government Railways 7th Class locomotives.

CGR 7th Class 4-8-0 1902
South African Classes 7C & 7CS 4-8-0

300px CGR 7th Class no. 765, SAR Class 7C no. 1065

Type and origin ♠ Original locomotive, as built ♥ Locomotive equipped with superheating Power type Steam Designer Cape Government Railways (H.M. Beatty) Builder Neilson, Reid and Company Serial number 6079-6088 Model CGR 7th Class Build date 1901 Total produced 10

Specifications Configuration 4-8-0 (Mastodon) Driver axle 2nd coupled axle Gauge 3 ft 6 in (1,067 mm) Cape gauge Leading dia Coupled dia Tender wheels as built 34 in (864 mm) retyred Wheelbase 46 ft 2 in (14,072 mm)  • Engine  • Leading 5 ft 3 in (1,600 mm)  • Coupled 12 ft (3,658 mm)  • Tender 16 ft 1 in (4,902 mm)  • Tender bogie 4 ft 7 in (1,397 mm) Length:  • Over couplers Height ♠♥ 12 ft 10 in (3,912 mm) Frame type Plate Axle load ♠♥  • Leading ♠♥  • 1st coupled ♠♥  • 2nd coupled ♠♥  • 3rd coupled ♠♥  • 4th coupled ♠♥  • Tender axle av. Adhesive weight ♠♥ Loco weight ♠♥ Tender weight Loco & tender weight ♠♥ Tender type ZC (2-axle bogies) ZA, ZB, ZC, ZE permitted Fuel type Coal Fuel capacity 5 LT 10 cwt (5.6 t) Water cap Boiler:  • Pitch ♠♥ 6 ft 10 in (2,083 mm)  • Diameter ♠♥ 4 ft 6 in (1,372 mm)  • Tube plates ♠♥ 10 ft 9 in (3,277 mm)  • Small tubes ♠ 185: ♥ 100:  • large tubes ♥ 18:  • Firebox type Round-top Boiler pressure 180 psi (1,241 kPa) Safety valve Ramsbottom Firegrate area ♠ 17.5 sq ft (1.63 m2) ♥ 18 sq ft (1.7 m2) Heating surface ♠ 1,089 sq ft (101.2 m2) ♥ 919 sq ft (85.4 m2)  • Tubes ♠ 976 sq ft (90.7 m2) ♥ 806 sq ft (74.9 m2)  • Firebox ♠♥ 113 sq ft (10.5 m2) Superheater:  • Heating area ♥ 206 sq ft (19.1 m2) Cylinders Two Cylinder size bore 23 in (584 mm) stroke Valve gear Stephenson Valve type ♠ Slide - ♥ Piston Couplers Bell link-and-pin AAR knuckle (1950s)

Performance figures Tractive effort ♠ 22,240 lbf (98.9 kN) @ 75% ♥ 20,990 lbf (93.4 kN) @ 75% Factor of adh 3.83

Career Operators Cape Government Railways South African Railways Class CGR 7th Class SAR Class 7C, Class 7CS Number in class 10 Numbers CGR 759-768 SAR 1059-1068 Delivered 1902 First run 1902 Withdrawn 1972

The leading coupled axle had flangeless wheels

The South African Railways Class 7C 4-8-0 of 1902 was a steam locomotive from the pre-Union era in the Cape of Good Hope.

In 1902, the Cape Government Railways placed its last ten 7th Class 4-8-0 Mastodon type steam locomotives in service on the Cape Eastern System. In 1912, when all these locomotives were assimilated into the South African Railways, they were renumbered and reclassified to Class 7C.

Manufacturer

The last of the 7th Class locomotives to be ordered by the Cape Government Railways (CGR), were ten for the Cape Eastern System. They were built by Neilson, Reid and Company in 1901, and delivered and placed in service in 1902, with engine numbers in the range from 759 to 768.

File:H.M. Beatty.jpg

H.M. Beatty

The original Cape 7th Class locomotive had been designed in 1892 by H.M. Beatty, at the time the Cape Government Railways (Western System) Locomotive Superintendent.

This last batch of locomotives differed from all previous 7th Class models in having a large commodious cab, with double windows on each side, similar to those which were fitted to the ex Central South African Railways (CSAR) Class 7B locomotives. This afforded better protection for the crew. They were more than 4 long tons (4.1 tonnes) heavier than the original 7th Class locomotives and they also had larger diameter boilers with a higher boiler pressure. Their power was further improved by their increased cylinder diameter.

Class 7 sub-classes

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. Although 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 required careful planning and was only implemented with effect from 1 January 1912.

When these locomotives were assimilated into the South African Railways (SAR) in 1912, they were renumbered in the range from 1059 to 1068 and designated Class 7C.

Other Class 7 locomotives which came onto the SAR roster from the CGR and other Colonial railways in the region, namely the CSAR, the Natal Government Railways (NGR), some from the Rhodesia Railways (RR) and, in 1925, from the New Cape Central Railways (NCCR), were grouped into another six sub-classes by the SAR, becoming SAR Classes 7, 7A, 7B and 7D to 7F.

Modifications

During the 1930s, many of the Class 7 series locomotives were equipped with superheated boilers and piston valves. On the Classes 7B and 7C, this conversion was sometimes indicated with an "S" suffix to the class number on the locomotive number plates, but on the rest of the Class 7 family, this distinction was not applied consistently. The superheated versions could be identified by the position of the chimney on the smokebox. The chimney was displaced forward on the superheated engines, to provide space behind it in the smokebox for the superheater header.

Service

In SAR service, the Class 7 series worked on every system in the country. During the South West African Campaign in World War I, 29 Class 7 series locomotives were sent to South West Africa (SWA) to assist the expeditionary forces. Three of these were Class 7C locomotives, numbers 1065 to 1067.

They proved so successful in that territory, that more were gradually transferred there in later years. By the time the Class 24 arrived in SWA in 1949, there were still 53 Class 7 series locomotives in use in SWA. Most remained there, and were only transferred back to South Africa when the Class 32-000 diesel-electric locomotives replaced them in 1961. In South Africa, they remained in branchline service, particularly at Tarkastad and Ladysmith and also on the Makadas line, from Touws River to Ladismith, until they were finally withdrawn in 1972.