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

South African Class NG G13 2-6-2+2-6-2
NG G13 49 at Sandstone Estates, near Ficksburg, 9 April 2006
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)[1]
Model Class NG G13
Build date 1927-1928
Total produced 12
Configuration 2-6-2+2-6-2 "Double Prairie" Garratt
Gauge 2 ft  (610 mm) 
Leading wheel
diameter		 21 in (533 mm)
Driver diameter 33 in (838 mm)
Trailing wheel
diameter		 21 in (533 mm)
Minimum curve 160 ft (48.768 m)
Wheelbase Total: 42 ft 9 in (13.030 m)
Engine units:
6 ft 3 in (1.905 m) coupled
13 ft 2 in (4.013 m) total
Length 48 ft 5.25 in (14.764 m)
Height 10 ft 4 in (3.150 m)
Frame Bar frame, 23 ft 9 in (7.239 m) between pivot centres
Axle load 7.075 long tons (7.2 t) on 1st driver
Weight on drivers 41.325 long tons (42.0 t)
Locomotive weight 61.675 long tons (62.7 t) w/o
Fuel type Coal
Fuel capacity 4 long tons (4.1 t)
Water capacity 1,285 imp gal (5,840 l) front
540 imp gal (2,500 l) rear
Boiler 4 ft 7.75 in (1.416 m) int dia
9 ft 3.625 in (2.835 m) int length
5 ft 5 in (1.651 m) pitch
Boiler pressure 180 psi (1,240 kPa)
Firegrate area 19.5 sq ft (1.812 m2)
Heating surface:
Tubes		 152 tubes 1.75 in (44.5 mm) dia
15 tubes 5.5 in (140 mm) dia
839 sq ft (77.946 m2)
Heating surface:
Firebox		 82.1 sq ft (7.627 m2)
Heating surface:
Total		 921.1 sq ft (85.573 m2)
Superheater area 149 sq ft (13.843 m2)
Cylinders Four
Cylinder size 12 in (305 mm) bore
16 in (406 mm) stroke
Valve gear Walschaerts
Tractive effort 18,850 lbf (83.8 kN) at 75% boiler pressure[2]
Career South African Railways
Class Class NG G13
Number in class 12
Number 49-50, 58-60, 77-83
Delivered 1927-1928
First run 1927
Withdrawn 1973
Disposition Retired

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 wheel arrangement in service on the Langkloof and Alfred County Railway narrow gauge lines.[3][4]

Contents

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.[4]

The initial order was for three Class NG G13 locomotives, numbers 58 to 60, 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.[3]

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 49 and 50, and even before these were delivered, another seven, numbers 77 to 83. The second and third orders were both delivered in 1928.[3]

Service

Natal

The first five locomotives, numbers 49, 50 and 58 to 60, 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 beet 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 77 to 83, initially all went to the Avontuur line where most of them remained for their entire service lives. In 1965 numbers 77 and 78 were exchanged for two Class NG G11 locomotives, numbers 54 and 55, 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 branch line.[3]

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 withrawn from service. Beginning at about the same time, the Natal locomotives were also progressively withdrawn from service.[3]

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 49 serving at the Sandstone Estates near Ficksburg, is being kept in excellent running order. Two were plinthed, number 80 at Joubertina station and number 81 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 circa 2009

Gallery

The main picture shows NG G13 number 49 at work on the Sandstone Estates, near Ficksburg, on 9 April 2006.

See also

References

  1. ^ The Garratt Locomotive - Garratt locomotives from other builders
  2. ^ South African Railways and Harbours Locomotive Diagram Book, 2’0” & 3’6” Gauge Steam Locomotives, 15 August 1941, as amended
  3. ^ a b c d e Paxton, Leith; Bourne, David (1985). Locomotives of the South African Railways (1st ed.). Cape Town: Struik. pp. 10-11, 107. ISBN 0869772112. 
  4. ^ a b Durrant, A E (1989). Twilight of South African Steam (1st ed.). Newton Abbott, London: David & Charles. p. 124. ISBN 0715386387. 
  5. ^ a b "South Africa Rail Offering". The New York Times. 1988-03-28. http://query.nytimes.com/gst/fullpage.html?res=940DEEDC1130F93BA15750C0A96E948260. 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. ^ "Humewood Road in Port Elizabeth". Steam Locomotives South Africa. 2009-08-23. http://steam-locomotives-south-africa.blogspot.com/2009/09/humewood-port-elizabeth-locomotive.html. Retrieved 2010-06-14.