South African Class 10D 4-6-2

CSAR Class 10 4-6-2 1910
South African Class 10D 4-6-2

300px CSAR no. 1002, SAR no. 779, c. 1910

Type and origin Power type Steam Designer Central South African Railways Builder American Locomotive Company Serial number 46715 Model CSAR Class 10 Build date 1910 Total produced 1

Specifications Configuration 4-6-2 (Pacific) Driver axle 2nd coupled axle Gauge 3 ft 6 in (1,067 mm) Cape gauge Leading dia Coupled dia 62 in (1,575 mm) Trailing dia 33 in (838 mm) Tender wheels Wheelbase 55 ft (16,764 mm)  • Engine 29 ft 8 in (9,042 mm)  • Leading 6 ft (1,829 mm)  • Coupled 11 ft 2 in (3,404 mm)  • Tender 16 ft 8 in (5,080 mm)  • Tender bogie 5 ft 4 in (1,626 mm) Length:  • Over couplers 62 ft 7 in (19,075 mm) Height Frame type Bar Axle load  • Leading  • 1st coupled  • 2nd coupled  • 3rd coupled  • Trailing  • Tender axle av. Adhesive weight Loco weight Tender weight w/o Loco & tender weight w/o Tender type 2-axle bogies Fuel type Coal Fuel capacity 10 LT (10.2 t) Water cap Boiler:  • Pitch 7 ft 8 in (2,337 mm)  • Diameter  • Tube plates  • Small tubes 132:  • large tubes 18  • Firebox type Belpaire Boiler pressure 170 psi (1,172 kPa) Safety valve Ramsbottom Firegrate area 35 sq ft (3.3 m2) Heating surface 1,981 sq ft (184.0 m2)  • Tubes 1,848 sq ft (171.7 m2)  • Firebox 133 sq ft (12.4 m2) Superheater Cole  • Heating area 353 sq ft (32.8 m2) Cylinders Two Cylinder size 21 in (533 mm) bore 28 in (711 mm) stroke Valve gear Walschaerts Valve type Piston Valve travel Valve lap 1 in (25 mm) Valve lead Couplers Bell link-and-pin

Performance figures Tractive effort 25,390 lbf (112.9 kN) @ 75%

Career Operators Central South African Railways South African Railways Class CSAR Class 10, SAR Class 10D Number in class 1 Numbers CSAR 1002, SAR 779 Delivered 1910 First run 1910 Withdrawn 1931

The 2nd coupled axle had flangeless wheels

The South African Railways Class 10D 4-6-2 of 1910 was a steam locomotive from the pre-Union era in the Transvaal.

In 1910, the Central South African Railways placed one American-built Class 10 4-6-2 Pacific type steam locomotive in service. When the South African Railways classification and renumbering took place in 1912, this locomotive was designated the sole member of Class 10D.

Manufacturer

One 4-6-2 Pacific type passenger locomotive was ordered by the Central South African Railways (CSAR) from the American Locomotive Company (ALCO) in 1910. It was built to very much the same specifications as that of the CSAR Class 10-2 of that same year, which was designed by CSAR Chief Mechanical Engineer (CME) G.G. Elliot.

The locomotive was slightly more powerful than the Class 10-2 and was designated Class 10 by the CSAR, with engine number 1002, along with the fifteen CSAR Class 10 4-6-2 locomotives which had been built by the North British Locomotive Company in 1904.

Characteristics

The cylinders were arranged outside the 4 inches (102 millimetres) thick bar frames, while the piston valves, arranged above the cylinders, were actuated by Walschaerts valve gear. Reversing was effected by means of a screw gear. The locomotive had a Belpaire firebox and, instead of the usual deep bridle casting, was built with a shallow casting and frame under the firebox, which permitted all firebox stays to be removed without lifting the boiler from the frame.

File:Cole superheater header.jpg

Cole superheater header

The locomotive was superheated, using the Cole double-header superheater system. It was somewhat similar to the Schmidt superheater system, except that the Cole type had two headers, arranged at either side of the smokebox, instead of one at the top.

Each of the eighteen diameter boiler flues contained four lengths of seamless steam pipes of outside diameter, arranged in double pairs which were connected at the back ends by return bends, with the two pairs connected to each other at the front by another return bend. This forced the steam to traverse the entire four pipe lengths before entering the steam chests. The two free front ends of each such foursome of pipes were bent around to meet the steam headers. This design of superheater produced a superheat of from 175 to 250 degrees Fahrenheit (79 to 121 degrees Celsius) above saturation temperature.

South African Railways

When the Union of South Africa was established on 31 May 1910, the three Colonial government railways (Cape Government Railways, Natal Government Railways and CSAR) 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.

In 1912, the sixteen CSAR Class 10 locomotives were renumbered on the South African Railways (SAR) roster. The fifteen older British-built locomotives retained their Class 10 designation on the SAR roster, but the ALCO-built one was designated the sole member of Class 10D and renumbered 779.

Service

The Class 10D was placed in service on fast passenger work in the Transvaal and later in the Orange Free State. It spent its last working years at Bloemfontein, until it was withdrawn from service in 1931 and scrapped.