South West African Class Hd

The South West African Class Hd 2-8-2 of 1912 was a narrow gauge steam locomotive from the German South West Africa era.

GSWA Class Hd 2-8-2 South West African Class Hd 2-8-2 South African Class NG5 2-8-2
No. 40 plinthed at Usakos, May 1984
Type and origin Power type Steam Designer Henschel and Son Builder Henschel and Son Serial number 10720-10722 Model Class Hd Build date 1912 Total produced 3
Specifications Configuration: ​  • Whyte 2-8-2  • UIC 1D1h2 Driver 3rd coupled axle Gauge 600 mm (1 ft 11+5⁄8 in) narrow Leading dia. 21+21⁄32 in (550 mm) Coupled dia. 33+7⁄8 in (860 mm) Trailing dia. 21+21⁄32 in (550 mm) Tender wheels 20+1⁄2 in (521 mm) Wheelbase 38 ft 6+5⁄8 in (11,751 mm) ​  • Axle spacing (Asymmetrical) 1-2: 3 ft 1+7⁄16 in (951 mm) 2-3: 3 ft 4+1⁄8 in (1,019 mm) 3-4: 3 ft 1+7⁄16 in (951 mm)  • Engine 17 ft 11⁄16 in (5,199 mm)  • Coupled 9 ft 7 in (2,921 mm)  • Tender 11 ft 5+3⁄4 in (3,499 mm)  • Tender bogie 3 ft 3+3⁄8 in (1,000 mm) Length: ​  • Over couplers 49 ft 9+1⁄4 in (15,170 mm) Height 10 ft 9+15⁄16 in (3,300 mm) Frame type Plate Loco weight 32 LT 17 cwt (33,380 kg) Tender weight 25 LT 11 cwt 3 qtr (26,000 kg) Total weight 58 LT 8 cwt 3 qtr (59,380 kg) Tender type 2-axle bogies Fuel type Coal Fuel capacity 2 LT 17 cwt (2.9 t) Water cap. 2,860 imp gal (13,000 L) Firebox: ​  • Type Round-top  • Grate area 16.7 sq ft (1.55 m2) Boiler: ​  • Pitch 5 ft 8+7⁄8 in (1,749 mm)  • Diameter 3 ft 11+3⁄4 in (1,213 mm)  • Tube plates 13 ft 1+1⁄2 in (4,000 mm)  • Small tubes 114: 1+3⁄4 in (44 mm)  • Large tubes 12: 4+23⁄32 in (120 mm) Boiler pressure 171 psi (1,179 kPa) Heating surface: ​  • Firebox 68 sq ft (6.3 m2)  • Tubes 900 sq ft (84 m2)  • Total surface 968 sq ft (89.9 m2) Superheater: ​  • Heating area 169 sq ft (15.7 m2) Cylinders Two Cylinder size 15+3⁄4 in (400 mm) bore 17+3⁄4 in (451 mm) stroke Valve gear Heusinger Valve type Piston Loco brake Air Train brakes Air & vacuum Couplers Buffer-and-chains
Performance figures Tractive effort 16,610 lbf (73.9 kN) @ 75%
Career Operators Otavi Mining and Railway Co. South African Railways Class GSWA Class Hd, SAR Class NG5 Number in class 3 Numbers SW40-SW42 Delivered 1912 First run 1912 Withdrawn 1960

In 1912, the German administration in German South West Africa acquired three Class Hd tender locomotives with a 2-8-2 "Mikado" wheel arrangement, for lease to the Otavi Mining and Railway Company to use on the line from Swakopmund to Karibib. When these locomotives were taken onto the roster of the South African Railways after the First World War, they retained their German classification and engine numbers, but with an "SW" prefix to their numbers.

When a system of grouping narrow gauge locomotives into classes was eventually introduced by the South African Railways, they were designated Class NG5 along with similar locomotives which were placed in service by the South African Railways in 1922.

Manufacturer

Increasing traffic demands arising from the copper mines at Tsumeb led to a requirement for more locomotives. Three narrow gauge 2-8-2 steam locomotives were built for the German administration in German South West Africa (GSWA) by Henschel and Son in Germany in 1912. They were designated Class Hd, numbered in the range from 40 to 42, and leased to the Otavi Mining and Railway Company for use on the section between Swakopmund and Karibib.

The "Hd" classification identified the locomotive type as the fourth class to have been built for GSWA by Henschel.

Characteristics

The locomotives were superheated, with Heusinger valve gear, piston valves and outside plate frames. Since they were to be used across the Namib Desert, they were equipped with dust covers to protect the motion from wind-blown sand. Their leading and trailing carrying wheels were not mounted in separate bogie trucks, but were rigidly mounted and arranged as radial axles to allow for sideways motion of the wheels in relation to the locomotive frame. This resulted in a rigid wheelbase of 17 feet 11⁄16 inch (5,199 millimetres), even though the leading carrying wheels were arranged to the rear instead of ahead of the cylinders.

As built, the sand boxes were mounted on top of the boiler aft of the dome. Their tenders, also built by Henschel, rode on two four-wheeled bogies and had a coal capacity of 2 long tons 17 hundredweight (2.9 tonnes) and a water capacity of 2,860 imperial gallons (13,000 litres). The engines were equipped for trains with air brakes, which was not yet in use in South Africa at the time.

South African Railways

After the First World War, when the former German colony came under South African administration and all railway operations in South West Africa (SWA) were taken over by the South African Railways (SAR) in 1922, these locomotives retained their Hd classification and engine numbers, but with an "SW" prefix to the numbers. This was to prevent confusion with the two Class NG1 narrow gauge locomotives of the SAR which were numbered NG40 and NG41.

In SAR service, the locomotives were also equipped with vacuum train brakes.

Reclassification

A system of grouping narrow gauge locomotives into classes was only adopted by the SAR somewhere between 1928 and 1930 and at that point these three locomotives, along with six similar locomotives which were built to a revised design and placed in service by the SAR in SWA in 1922, were all designated Class NG5. The original three locomotives retained their original German engine numbers, but the SW prefix was done away with since the two Class NG1 locomotives with duplicate engine numbers were being withdrawn from service at the time.

Service

They remained on the SWA for their entire working lives, and all were withdrawn when the 2 ft gauge lines of the SWA system were widened to Cape gauge in 1960. Since they were unsuitable for use on the 2 ft line in the Langkloof, all six of the 1922 vintage Class NG5 locomotives were scrapped in 1962.

Number plate and plaques on No. 41, Otjiwarongo, 2011

Two of the 1912 ex-Class Hd locomotives were preserved. No. 40 was plinthed on the Usakos railway station platform while No. 41 was plinthed outside Otjiwarongo railway station.

Commemoration

A postage stamp depicting the Class Hd locomotive was one of a set of four commemorative South West African postage stamps which were issued on 2 August 1985 to commemorate the narrow gauge locomotives which pioneered railways in the territory. The stamp design was by the noted stamp designer and artist Koos van Ellinckhuijzen.

Illustration

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  Works picture of Class Hd no. 40, c. 1912