South African Class 10 4-6-2

CSAR Class 10 4-6-2 1904 South African Class 10 4-6-2
SAR no. 738 (ex CSAR no. 656) at Sydenham Loco depot, 4 September 1966
Type and origin ♠ Type XM2 tender - ♥ Type XP1 tender (No. 746) Power type Steam Designer Central South African Railways (P.A. Hyde) Builder North British Locomotive Company Serial number 16194-16203, 16226-16230 Model CSAR Class 10 Build date 1904 Total produced 15
Specifications Configuration: ​  • Whyte 4-6-2 (Pacific)  • UIC 2'C1'h2 Driver 2nd coupled axle Gauge 3 ft 6 in (1,067 mm) Cape gauge Leading dia. 28 1⁄2 in (724 mm) Coupled dia. 62 in (1,575 mm) as built 63 in (1,600 mm) no. 745 Trailing dia. 33 in (838 mm) Tender wheels ♠ 33 1⁄2 in (851 mm) as built 34 in (864 mm) retyred ♥ 34 in (864 mm) Wheelbase 56 ft 4 in (17,170 mm)  • Engine 30 ft 2 in (9,195 mm)  • Leading 6 ft (1,829 mm)  • Coupled 10 ft 10 in (3,302 mm)  • Tender ♠♥ 16 ft 9 in (5,105 mm)  • Tender bogie ♠♥ 4 ft 7 in (1,397 mm) Length: ​  • Over couplers 64 ft 6 3⁄4 in (19,679 mm) Height 12 ft 10 in (3,912 mm) Frame type Plate Axle load 15 LT 10 cwt (15,750 kg)  • Leading 13 LT 10 cwt (13,720 kg)  • 1st coupled 15 LT (15,240 kg)  • 2nd coupled 15 LT 10 cwt (15,750 kg)  • 3rd coupled 15 LT 10 cwt (15,750 kg)  • Trailing 13 LT 5 cwt (13,460 kg)  • Tender bogie Bogie 1: ♠ 24 LT 4 cwt (24,590 kg) ♥ 27 LT 10 cwt (27,940 kg) Bogie 2: ♠ 25 LT 3 cwt (25,550 kg) ♥ 23 LT 11 cwt (23,930 kg)  • Tender axle ♠ 12 LT 11 cwt 2 qtr (12,780 kg) ♥ 13 LT 15 cwt (13,970 kg) Adhesive weight 46 LT (46,740 kg) Loco weight 72 LT 15 cwt (73,920 kg) Tender weight ♠ 49 LT 7 cwt (50,140 kg) ♥ 51 LT 1 cwt (51,870 kg) Total weight ♠ 122 LT 2 cwt (124,100 kg) ♥ 123 LT 16 cwt (125,800 kg) Tender type ♠ XM2 (2-axle bogies) ♥ XP1 (2-axle bogies) XC, XC1, XD, XE, XE1, XF, XF1, XF2, XJ, XM, XM1, XM2, XM3, XM4, XP1, XS permitted Fuel type Coal Fuel capacity ♠♥ 10 LT (10.2 t) Water cap ♠ 4,000 imp gal (18,200 l) ♥ 4,250 imp gal (19,300 l) Firebox type Belpaire  • Firegrate area 35 sq ft (3.3 m2) Boiler: ​  • Pitch 7 ft 4 in (2,235 mm)  • Diameter 4 ft 6 3⁄4 in (1,391 mm)  • Tube plates 18 ft 6 1⁄2 in (5,652 mm)  • Small tubes 92: 2 1⁄4 in (57 mm)  • Large tubes 18: 5 1⁄4 in (133 mm) Boiler pressure 190 psi (1,310 kPa) Safety valve Ramsbottom Heating surface 1,588 sq ft (147.5 m2)  • Tubes 1,463 sq ft (135.9 m2)  • Firebox 125 sq ft (11.6 m2) Superheater: ​  • Heating area 384 sq ft (35.7 m2) Cylinders Two Cylinder size 19 1⁄2 in (495 mm) bore 28 in (711 mm) stroke Valve gear Walschaerts Valve type Piston Couplers Johnston link-and-pin AAR knuckle (1930s)
Performance figures Tractive effort 24,470 lbf (108.8 kN) @ 75%
Career Operators Central South African Railways South African Railways Class CSAR & SAR Class 10 Number in class 15 Numbers CSAR 650-664, SAR 732-746 Delivered 1904 First run 1904 Withdrawn 1972
The 2nd coupled axle had flangeless wheels

The South African Railways Class 10 4-6-2 of 1904 was a steam locomotive from the pre-Union era in Transvaal Colony.

In July 1904, the Central South African Railways placed fifteen Class 10 steam locomotives with a 4-6-2 Pacific type wheel arrangement in service. In 1912, when they were assimilated into the South African Railways, they were renumbered but retained their Class 10 designation.

Fifteen 4-6-2 Pacific type passenger locomotives, designed by Central South African Railways (CSAR) Chief Locomotive Superintendent P.A. Hyde, were ordered from the North British Locomotive Company (NBL) and delivered in 1904, numbered in the range from 650 to 664. They were designated Class 10 by the CSAR.

The Class 10 was designed by Hyde to take full advantage of the new 80 pounds per yard (40 kilograms per metre) track of the CSAR, which was gradually replacing the old 60 pounds per yard (30 kilograms per metre) sections on mainlines. The locomotive had plate frames, a wide Belpaire firebox, outside admission piston valves and Walschaerts valve gear, and was superheated. Its 62 inches (1,575 millimetres) coupled wheels were 2 inches (51 millimetres) larger in diameter than those of H.M. Beatty's Karoo Class Pacific which had entered service on the Cape Government Railways (CGR) the year before. At the time, the CSAR Classes 10 and 11 which were acquired simultaneously, were the heaviest and largest locomotives built for 3 feet 6 inches (1,067 millimetres) gauge.

These locomotives were to form the basis for further development of the Pacific type, which was to become the standard express passenger steam locomotive type in South Africa. They were handsome locomotives and their appearance was enhanced by the use of planished steel plates to cover the boiler and cylinder lagging. They were equipped with two whistles of different tones and a steam turbine generator, mounted on the smokebox between the headlight and the chimney, to power the Edwards headlight.