South African Class 4 4-8-2

CGR Mountain 4-8-2
South African Class 4 4-8-2

300px SAR Class 4 no. 1478 at Worcester, c. 1930

Type and origin Power type Steam Designer Cape Government Railways (H.M. Beatty) Builder North British Locomotive Company Serial number 19242-19243 Model CGR 4-8-2 Build date 1911 Total produced 2

Specifications Configuration 4-8-2 (Mountain) Driver axle 2nd coupled axle Gauge 3 ft 6 in (1,067 mm) Cape gauge Leading dia Coupled dia 54 in (1,372 mm) Trailing dia 33 in (838 mm) Tender wheels as built 34 in (864 mm) retyred Wheelbase  • Engine 31 ft 11 in (9,728 mm)  • Leading 6 ft 2 in (1,880 mm)  • Coupled 14 ft 5 in (4,394 mm)  • Tender 16 ft 1 in (4,902 mm)  • Tender bogie 4 ft 7 in (1,397 mm) Wheel spacing (Assymetrical) 1-2: 4 ft 10 in (1,473 mm) 2-3: 4 ft 9 in (1,448 mm) 3-4: 4 ft 10 in (1,473 mm) Length:  • Over couplers Height 12 ft 10 in (3,912 mm) Frame type Bar Axle load  • Leading  • 1st coupled  • 2nd coupled  • 3rd coupled  • 4th coupled  • Tender bogie Bogie 1: Bogie 2:  • Tender axle Adhesive weight Loco weight Tender weight w/o Loco & tender weight w/o Tender type XJ (2-axle bogies) Fuel type Coal Fuel capacity 6 LT 10 cwt (6.6 t) Water cap Boiler:  • Pitch 7 ft 6 in (2,286 mm)  • Diameter  • Tube plates 18 ft (5,486 mm)  • Small tubes 201:  • Firebox type Round-top, combustion chamber Boiler pressure 180 psi (1,241 kPa) Safety valve Ramsbottom (No. 850/1477) Cole's Pop (No. 851/1478) Firegrate area 37 sq ft (3.4 m2) Heating surface 2,317 sq ft (215.3 m2)  • Tubes 2,131 sq ft (198.0 m2)  • Firebox 186 sq ft (17.3 m2) Cylinders Two Cylinder size bore 28 in (711 mm) stroke Valve gear Stephenson Valve type "D" slide Couplers Bell link-and-pin

Performance figures Tractive effort 29,420 lbf (130.9 kN) @ 75%

Career Operators Cape Government Railways South African Railways Class SAR Class 4 Number in class 2 Numbers CGR 850-851 SAR 1477-1478 Delivered 1911 First run 1911 Withdrawn 1938

The leading coupled axle had flangeless wheels

The South African Railways Class 4 4-8-2 of 1911 was a steam locomotive from the pre-Union era in the Cape of Good Hope.

In 1911, the Cape Government Railways placed two steam locomotives with a 4-8-2 Mountain type wheel arrangement in service. A year later, when they were assimilated into the South African Railways, they were renumbered and classified as Class 4.

Manufacturer

The first 4-8-2 Mountain type locomotive of the Cape Government Railways (CGR) was designed at the Salt River shops as a heavy mixed traffic engine by H.M. Beatty, the Chief Locomotive Superintendent of the CGR from 1896 to 1910. Two locomotives were built by the North British Locomotive Company (NBL) and delivered in March 1911. The locomotives were a further development of the two experimental locomotives which had been placed in service by the CGR in 1906, the CGR Class 9 2-8-2 (SAR Class Experimental 5) and the CGR Class 10 4-8-0 (SAR Class Experimental 6), both built by Kitson and Company.

Characteristics

File:H.M. Beatty.jpg

H.M. Beatty

The Class 4 had bar frames, Stephenson valve gear with flat "D" slide valves arranged above the cylinders, and used saturated steam. The boiler was equipped with a combustion chamber, which was carried forward 2 feet (610 millimetres) from the firebox into the boiler barrel, of which the diameter was increased at the hind course to suit. This reduced the distance between the tube plates to 18 feet (5,486 millimetres) and made them excellent steamers.

While they were numbered 850 and 851 in the CGR numbering sequence, they were not designated a classification. The two engines were not identical, no. 850 being equipped with the usual Ramsbottom safety valves while no. 851 had Cole’s muffled type Pop safety valves, both set for 180 pounds per square inch (1,241 kilopascals) boiler pressure. They were delivered with Type XJ tenders with a 6 long tons 10 hundredweight (6.6 tonnes) coal and a water capacity.

South African Railways

File:Cape Colony railways map 1910.svg

Railway network of the Cape Government Railways in 1910, upon the establishment of the Union of South Africa and the South African Railways

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, with Sir William Hoy appointed as its first General Manager, 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.

In 1912, these two locomotives were renumbered to 1477 and 1478 and classified as Class 4 on the SAR.

Service

Both of them were placed in service in the Karoo, working between Touws River and Beaufort West. In later years they were stationed at Worcester, from where they were used extensively on and around the Cape Western system’s mainline, working pick-up goods trains to De Doorns in the Hex River valley and on the Mosselbaai line via Robertson.

They were withdrawn from service by 1938.

Illustration

The main picture shows SAR no. 1478 at Worcester, c. 1930, with Cole's Pop safety valves.

• CGR Mountain no. 850.jpg

  GCR no. 850, SAR no. 1477, with Ramsbottom safety valves