South African Class NG G13 2-6-2+2-6-2

South African Class NG G13 2-6-2+2-6-2

NG G13 no. 49 at Sandstone Estates, near Ficksburg, 9 April 2006
Type and origin
Power type Steam
Designer Hannoversche Maschinenbau AG
South African Railways
Builder Hannoversche Maschinenbau AG
Serial number 10549-10551 (58-60)
10598-10599 (50 & 49)
10629-10635 (77-83)
Model Class NG G13
Build date 1927-1928
Total produced 12
Specifications
Configuration 2-6-2+2-6-2 "Double Prairie" Garratt
Gauge 2 ft (610 mm) narrow gauge
Leading dia 21 in (533 mm)
Driver diameter 33 in (838 mm)
Trailing dia 21 in (533 mm)
Minimum curve 160 ft (48,768 mm)
Wheelbase Total: 42 ft 9 in (13,030 mm)
Engine units:
6 ft 3 in (1,905 mm) coupled
13 ft 2 in (4,013 mm) total
Length 48 ft 5.25 in (14,764 mm)
Height 10 ft 4 in (3,150 mm)
Frame Bar frame, 23 ft 9 in (7,239 mm) between pivot centres
Axle load 7.075 long tons (7.2 t) on 1st driver
Adhesive weight 41.325 long tons (42.0 t)
Loco weight 61.675 long tons (62.7 t) w/o
Fuel type Coal
Fuel capacity 4 long tons (4.1 t)
Water cap 1,285 imp gal (5,840 l) front
540 imp gal (2,500 l) rear
Firebox:
  Firegrate area
19.5 sq ft (1.812 m2)
Boiler 4 ft 7.75 in (1,416 mm) inside diameter
9 ft 3.625 in (2,835 mm) inside length
5 ft 5 in (1,651 mm) pitch
Boiler pressure 180 psi (1,240 kPa)
Heating surface 921.1 sq ft (85.573 m2)
  Tubes 152 tubes 1.75 in (44 mm) diameter
15 tubes 5.5 in (140 mm) diameter
839 sq ft (77.946 m2)
  Firebox 82.1 sq ft (7.627 m2)
Superheater:
  Heating area
149 sq ft (13.843 m2)
Cylinders Four
Cylinder size 12 in (305 mm) bore
16 in (406 mm) stroke
Valve gear Walschaerts
Performance figures
Tractive effort 18,850 lbf (84 kN) at 75% pressure
Career
Operators South African Railways
Class Class NG G13
Number in class 12
Numbers 49-50, 58-60, 77-83
Delivered 1927-1928
First run 1927
Withdrawn 1973

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The South African Railways Class NG G13 2-6-2+2-6-2 of 1927 is a narrow gauge articulated steam locomotive.

In 1927 and 1928 the South African Railways placed twelve Class NG G13 Garratt articulated steam locomotives with a 2-6-2+2-6-2 Double Prairie type wheel arrangement in service on the Langkloof and Alfred County Railway narrow gauge lines.[1][2]

Manufacturer

In 1927 Hannoversche Maschinenbau AG (Hanomag), in consultation with the South African Railways (SAR), designed a locomotive which was to become the standard 2 feet (610 millimetres) narrow gauge Garratt locomotive in South Africa for the next forty years. It was greatly improved from the Class NG G11, with trailing wheels added to each engine unit, outside bar frames instead of plate frames, round top fireboxes instead of Belpaire fireboxes, and larger dimensions in most respects except the grate area.[2][3]

The initial order was for three Class NG G13 locomotives, numbered in the range from NG58 to NG60, that were delivered and placed in service in 1927. These locomotives were superheated and sported an extremely compact arrangement of Walschaerts valve gear and outside bar frames. The pilot wheels were arranged as conventional pony trucks, while the inner carrying wheels were built to the Gölsdorf system that allowed the axle some lateral movement.[1][4]

Performance trials of the Class NG G13 proved it to be both powerful and free steaming, despite having a smaller grate area than the predecessor Class NG G11. This resulted in an immediate order for another two locomotives, numbers NG49 and NG50, and even before these were delivered, another seven, numbered in the range from NG77 to NG83. The second and third orders were both delivered in 1928.[1]

Service

Natal

The first five locomotives, numbers NG49, NG50 and NG58 to NG60, were used almost exclusively on the narrow gauge lines in Natal. Some of these routes had curves of 45 metres (148 feet) and gradients of up to 3 in 100, but the Garratts were well suited to hauling the diverse freight traffic of pulpwood, sugar cane and bananas.

One of these lines, the 122 kilometres (76 miles) branch from Port Shepstone to Paddock via Izotsha, was eventually privatised as the Port Shepstone and Alfred County Railway (ACR) after the SAR ceased operations there in 1986. The ACR conducted both freight and tourist passenger operations, with the tourist train becoming known as the Banana Express.[5]

Cape Province

The third order of seven locomotives, numbers NG77 to NG83, initially all went to the Avontuur line where most of them remained for their entire service lives. In 1965 numbers NG77 and NG78 were exchanged for two Class NG G11 locomotives, numbers NG54 and NG55, from the Natal system. The Avontuur locomotives ended their service lives working out of Loerie, either hauling limestone trains to Van Stadens or doing duty on the Patensie branchline.[1]

The 283 kilometres (176 miles) Avontuur line stretches from Port Elizabeth to Avontuur through the Langkloof. The narrow gauge track enabled the trains to pick up fruit virtually directly from the Langkloof fruit farms and ship it directly, without reloading, to the ripening warehouses, distributors and ships at Port Elizabeth. The route became known as the Apple Express after the main crop it transported. The line also carried pulpwood, as well as limestone to supply the cement factories which were located on the route.[5]

Retirement

When the lower section of the Avontuur line was dieselised upon the arrival of the Class 91-000 diesel-electric locomotives in 1973, the Class NG G13 locomotives were all withdrawn from service. Beginning at about the same time, the Natal locomotives were also progressively withdrawn from service.[1]

Preservation

Since withdrawal from SAR service, some locomotives were sold into private hands, while others ended up in various degrees of preservation ranging across the spectrum from operational to plinthing to total abandonment. One known ex SAR Class NG G13 Garratt, number NG49 serving at the Sandstone Estates near Ficksburg, is being kept in excellent running order. Two were plinthed, number NG80 at Joubertina station and number NG81 at Patensie station.

The last known locations of all the Class NG G13 locomotives are shown in the table.[6]

South African Class NG G13 2-6-2+2-6-2
Locations as at c. 2009

Illustration

The main picture and the following photographs offer views of both sides and ends of the Class NG G13 locomotive.

References

  1. 1 2 3 4 5 Paxton, Leith; Bourne, David (1985). Locomotives of the South African Railways (1st ed.). Cape Town: Struik. pp. 10–11, 107. ISBN 0869772112.
  2. 1 2 Durrant, A E (1989). Twilight of South African Steam (1st ed.). Newton Abbott, London: David & Charles. p. 124. ISBN 0715386387.
  3. Hamilton, Gavin N., The Garratt Locomotive - Garratt Locomotives from Other Builders, retrieved 10 November 2012
  4. South African Railways and Harbours Locomotive Diagram Book, 2’0” & 3’6” Gauge Steam Locomotives, 15 August 1941, as amended
  5. 1 2 "South Africa Rail Offering". The New York Times. 1988-03-28. Retrieved 2010-05-23.
  6. Middleton, John N. (2002). Railways of Southern Africa Locomotive Guide - 2002 (as amended by Combined Amendment List 4, January 2009) (2nd, Dec 2002 ed.). Herts, England: Beyer-Garratt Publications. p. 31.
  7. Exmoor Steam Railway and its history
  8. 1 2 3 Stars of Sandstone 2017 (sic: 2015) - Newsletter Number III, p. 4
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