South African Class S1 0-8-0

South African Class S1 0-8-0

No. 3814 in Germiston yard, August 1973

Type and origin Power type Steam Designer South African Railways (Dr. M.M. Loubser) Builder South African Railways North British Locomotive Company Serial number NBL 27261-27285 Model Class S1 Build date 1947-1953 Total produced 37

Specifications Configuration 0-8-0 (Eight-coupled) Driver 3rd coupled axle Gauge 3 ft 6 in (1,067 mm) Cape gauge Coupled dia. 48 in (1,219 mm) Tender wheels 34 in (864 mm) Minimum curve 165 ft (50 m) Wheelbase 49 ft 1⁄8 in (14,938 mm)  • Engine 14 ft 9 in (4,496 mm)  • Coupled 14 ft 9 in (4,496 mm)  • Tender 20 ft 5 in (6,223 mm)  • Tender bogie 6 ft 2 in (1,880 mm) Length: ​  • Over couplers 64 ft 1⁄4 in (19,514 mm) Height 12 ft 11 7⁄8 in (3,959 mm) Frame type Bar Axle load 19 LT 18 cwt (20,220 kg)  • 1st coupled 17 LT 18 cwt (18,190 kg)  • 2nd coupled 19 LT 18 cwt (20,220 kg)  • 3rd coupled 19 LT 7 cwt (19,660 kg)  • 4th coupled 17 LT 5 cwt (17,530 kg)  • Tender bogie Bogie 1: 31 LT 10 cwt (32,010 kg) Bogie 2: 34 LT 3 cwt (34,700 kg)  • Tender axle 17 LT 1 cwt 2 qtr (17,350 kg) Adhesive weight 74 LT 8 cwt (75,590 kg) Loco weight 74 LT 8 cwt (75,590 kg) Tender weight 65 LT 13 cwt (66,700 kg) Total weight 140 LT 1 cwt (142,300 kg) Tender type JT1 (2-axle bogies) Fuel type Coal Fuel capacity 11 LT (11.2 t) Water cap 6,000 imp gal (27,300 l) Firebox type Round-top  • Firegrate area 42 sq ft (3.9 m2) Boiler: ​  • Pitch 9 ft 2 in (2,794 mm)  • Diameter 5 ft 10 1⁄2 in (1,791 mm)  • Tube plates 13 ft 2 11⁄16 in (4,031 mm)  • Small tubes 151: 2 in (51 mm)  • Large tubes 30: 5 1⁄2 in (140 mm) Boiler pressure 180 psi (1,241 kPa) Safety valve Pop Heating surface 1,820 sq ft (169 m2)  • Tubes 1,600 sq ft (150 m2)  • Arch tubes 52 sq ft (4.8 m2)  • Firebox 168 sq ft (15.6 m2) Superheater: ​  • Heating area 428 sq ft (39.8 m2) Cylinders Two Cylinder size 23 1⁄4 in (591 mm) bore 25 in (635 mm) stroke Valve gear Walschaerts Valve type Piston Valve travel 5 1⁄16 in (129 mm) Couplers AAR knuckle

Performance figures Tractive effort 38,000 lbf (170 kN) @ 75% Factor of adh. 4•48

Career Operators South African Railways Class Class S1 Number in class 37 Numbers 374-385, 3801-3825 Delivered 1947-1954 First run 1947 Withdrawn 1980s

The 3rd coupled axle had flangeless wheels

The South African Railways Class S1 0-8-0 of 1947 was a steam locomotive.

In 1947, the South African Railways placed twelve Class S1 shunting steam locomotives with a 0-8-0 eight-coupled wheel arrangement in service, built in the Salt River workshops in Cape Town. A further 25, built in Scotland, were placed in service in 1954.

The Class S1 was the fifth locomotive type to be designed and built in South Africa, after the Natal Government Railways 4-6-2TT Havelock of 1888, the Class 2C of 1910, the Class 20 of 1935 and the Class ES of 1936.

A huge increase in traffic before and during the Second World War years led to the available dedicated shunting locomotives of the South African Railways (SAR) being very much over-taxed, to the extent that they had to be supplemented by mainline locomotives. By 1943, the options were to either relegate Class 14 and other mainline engines to shunting duties, or to augment the number of existing Class S shunting locomotives. The requirement for a shunting locomotive type, more powerful than the Class S, was identified, but since the war was still in progress, it was not viable to obtain locomotives from the usual overseas suppliers.

Dr. M.M. Loubser, Chief Mechanical Engineer (CME) of the SAR from 1939 to 1949, therefore prepared designs for a larger version of the Class S locomotive which could be built in the SAR's own workshops. The result was the Class S1 0-8-0 shunting locomotive, of which the first of twelve was delivered from the Salt River shops in Cape Town in October 1947.

Twelve locomotives were built, numbered in the range from 374 to 385. The first locomotive was formally handed over to the Operating Department by the senior member of the Railway Board, Mr F.T. Bates. In honour of the occasion and in view of the approaching South African Tercentenary celebrations, it was named Voortrekker.

A further 25 Class S1 locomotives were subsequently ordered from the North British Locomotive Company (NBL) in Glasgow. They were built in 1953 and delivered in 1953 and 1954, numbered in the range from 3801 to 3825.

Even though it was not wholly a South African product with its imported main bar frames, tyres, superheater elements and some proprietary fittings, the Class S1 was the fifth recorded instance of locomotives designed and constructed in South African workshops, after the Natal Government Railways' engine Havelock of 1888, the Class 2C of 1910, the Class 20 of 1935 and the Class ES of 1936. The Class S1 was, however, the first steam locomotive to be home-built in quantity.