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Specifications
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)
Safety valve	Salter
Heating surface:
• Firebox	68 sq ft (6.3 m2)
• Tubes	880 sq ft (82 m2)
• Total surface	948 sq ft (88.1 m2)
Superheater:;
• Heating area	145 sq ft (13.5 m2)
Cylinders	Two
Cylinder size	15+3⁄4 in (400 mm) bore; 17+3⁄4 in (451 mm) stroke
Valve gear	Walschaerts
Valve type	Slide
Loco brake	Vacuum
Train brakes	Vacuum
Couplers	Buffer-and-chains

Type and origin
Type and origin
Power type	Steam
Designer	Henschel & Son
Builder	Henschel & Son
Serial number	18578-18583
Model	Class NG5
Build date	1921
Total produced	6

South African Class NG5 2-8-2
South African Class NG5 2-8-2
	Class NG5, c. 1960
Power type
Type and origin
Power type	Steam
Designer	Henschel & Son
Builder	Henschel & Son
Serial number	18578-18583
Model	Class NG5
Build date	1921
Total produced	6
Configuration:;
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)
Safety valve	Salter
Heating surface:
• Firebox	68 sq ft (6.3 m2)
• Tubes	880 sq ft (82 m2)
• Total surface	948 sq ft (88.1 m2)
Superheater:;
• Heating area	145 sq ft (13.5 m2)
Cylinders	Two
Cylinder size	15+3⁄4 in (400 mm) bore; 17+3⁄4 in (451 mm) stroke
Valve gear	Walschaerts
Valve type	Slide
Loco brake	Vacuum
Train brakes	Vacuum
Couplers	Buffer-and-chains
Tractive effort
Performance figures
Tractive effort	16,610 lbf (73.9 kN) @ 75%
Operators
Career
Operators	South African Railways
Class	Class NG5
Number in class	6
Numbers	NG71-NG76
Delivered	1922
First run	1922
Withdrawn	1960

The South African Railways Class NG5 2-8-2 of 1922 was a class of narrow-gauge steam locomotives.

In 1922, the South African Railways placed six narrow-gauge steam locomotives with a 2-8-2 Mikado type wheel arrangement in service on the Otavi Railway in South West Africa. When a system of grouping narrow-gauge locomotives into classes was eventually introduced somewhere between 1928 and 1930, they were designated Class NG5.^[1]^[2]

Manufacturer

Six narrow-gauge 2-8-2 steam locomotives were built for the South African Railways (SAR) by Henschel and Son in Germany in 1921. They were built to the same design as the three Class Hd locomotives which had been built in 1912 for the German administration in German South West Africa (GSWA) for leasing to the Otavi Mining and Railway Company. The locomotives, numbered in the range from NG71 to NG76, were delivered in 1922.^[1]^[2]^[3]

Characteristics

Like their predecessor Class Hd, they were superheated, with Walschaerts valve gear and outside plate frames. The new locomotives differed from the Class Hd in having different boilers, which were of the same dimensions but with a different tube arrangement and, as a consequence, a slightly reduced total heating surface.^[4]^[5]

In keeping with SAR practice at the time, they had vacuum train brakes instead of the air brakes which the Class Hd was equipped with. They had slide valves which was unusual on a superheated locomotive, instead of piston valves like the Class Hd. As built, the sand boxes were mounted on top of the boiler between the chimney and the steam dome.^[1]^[4]^[5]

Their rigidly mounted leading and trailing carrying wheels were also arranged as radial axles to allow for sideways motion of the wheels in relation to the locomotive frame, since the locomotive did not have separate bogie trucks. As on the Class Hd, 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.^[2]^[4]^[5]

Classification

In service, these six locomotives and the three Class Hd locomotives were operated in a common pool. The system of grouping narrow-gauge locomotives into classes was only adopted by the SAR at some date between 1928 and 1930. At that point, these six locomotives and the three Class Hd locomotives were all designated Class NG5.^[1]^[2]^[4]

Service

The 1922-vintage Class NG5 was placed in service on the 352-mile long (566-kilometre) narrow-gauge line from Swakopmund on the Atlantic coast to Tsumeb and Grootfontein in South West Africa (SWA). They spent their whole service life in SWA, except for a brief period when one of them was sent to the Avontuur Railway in the Eastern Cape for trials. However, since it jammed on the tighter curves in the Langkloof despite having one set of flangeless coupled wheels, it was soon returned to SWA.^[1]

The Class NG5 were all withdrawn from service when the narrow-gauge system in SWA was regauged to Cape gauge in 1960. Since they were unsuitable for use in the Langkloof, all six 1922-vintage Class NG5 locomotives were sold as scrap in 1962.^[1]

Preservation

While all of the Class NG5 were scrapped, two of the similar Class Hd locomotives have been preserved and plinthed at Otjiwarongo and Usakos respectively.^[1]

References

^ ^a ^b ^c ^d ^e ^f ^g Paxton, Leith; Bourne, David (1985). Locomotives of the South African Railways (1st ed.). Cape Town: Struik. pp. 102, 110, 116–117. ISBN 0869772112.
^ ^a ^b ^c ^d Espitalier, T.J.; Day, W.A.J. (1947). The Locomotive in South Africa – A Brief History of Railway Development. Chapter VII – South African Railways (Continued). South African Railways and Harbours Magazine, December 1947. pp. 1033-1034.
^ Henschel-Lieferliste (Henschel & Son works list), compiled by Dietmar Stresow
^ ^a ^b ^c ^d South African Railways and Harbours Narrow Gauge Locomotive Diagram Book, 2'0" Gauge, S.A.R. Mechanical Dept. Drawing Office, Pretoria, 28 November 1932
^ ^a ^b ^c South African Railways and Harbours Locomotive Diagram Book, 2'0" & 3'6" Gauge Steam Locomotives, 15 August 1941, as amended