South African Class NG G16 2-6-2+2-6-2

South African Class NG G16 2-6-2+2-6-2

No. NG113 at Sandstone Estates, 9 April 2006
Type and origin
Power type Steam
Designer Hannoversche Maschinenbau AG
South African Railways
Builder Société Anonyme John Cockerill
Beyer, Peacock and Company
Hunslet-Taylor
Serial number Cockerill 3265-3268/1937
Beyer, Peacock 6919-6926/1939, 7426-7432/1951, 7862-7868/1958
Hunslet-Taylor 3894-3901/1967-1968
Model Class NG G16
Build date 1937-1968
Total produced 34
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: 43 ft 3 in (13,183 mm)
Engine units:
6 ft 3 in (1,905 mm) coupled
13 ft 10.5 in (4,229 mm) total
Length 48 ft 3.25 in (14,713 mm)
Width 7 ft (2,134 mm)
Height 10 ft 4 in (3,150 mm)
Frame Bar frame, 23 ft 9 in (7,239 mm) between pivot centres
Axle load All but 137-143:
6.9 long tons (7.0 t) on 1st driver
137-143:
6.9 long tons (7.0 t) on 2nd driver
Adhesive weight All but 137-143:
39.25 long tons (39.9 t)
137-143:
40.125 long tons (40.8 t)
Loco weight All but 137-143:
59.1 long tons (60.0 t)
137-143:
61.275 long tons (62.3 t)
Fuel type Coal
Fuel capacity All but 137-143:
4 long tons (4.1 t)
137-143:
6.2 long tons (6.3 t)
Water cap All but 137-143, 149-156:
1,285 imp gal (5,840 l) front
540 imp gal (2,500 l) rear
137-143:
1,325 imp gal (6,020 l) front only
149-156:
1,325 imp gal (6,020 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
Alfred County Railway
Welsh Highland Railway
Class Class NG G16
Number in class 34
Numbers NG85-NG88, NG109-NG116, NG125-NG131, NG137-NG143, NG149-NG156
Delivered 1937-1968
First run 1937

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The South African Railways Class NG G16 2-6-2+2-6-2 of 1937 is a narrow gauge steam locomotive.

Between 1937 and 1968 the South African Railways placed thirty-four Class NG G16 Garratt articulated steam locomotives with a 2-6-2+2-6-2 Double Prairie type wheel arrangement in service on the Avontuur Railway and on the Natal narrow gauge lines.[1][2]

Manufacturers

The success of the Class NG G13 narrow gauge Garratts that were introduced by the South African Railways (SAR) in 1927 led to a decision that any additional narrow gauge articulated locomotives would be of the same design. Altogether thirty-four more 2-6-2+2-6-2 Double Prairie type narrow gauge locomotives were built, spread over five orders from three manufacturers over a span of thirty-one years.[2][3][4][5]

Cockerill

In 1937 Société Anonyme John Cockerill of Seraing in Belgium delivered four new 2-6-2+2-6-2 locomotives, numbered in the range from NG85 to NG88, which were so similar to the older locomotives that they were initially classified as Class NG G13 as well. However, in view of the fact that all the carrying wheels were fitted with roller bearing axle boxes and arranged as pony trucks, compared to the Class NG G13 whose inner carrying wheels were built to the Gölsdorf system that allowed the axle some lateral movement, it was soon decided to reclassify them to Class NG G16.[2][4]

These pre-war locomotives, like the earlier Class NG G13 locomotives, were built with riveted coal and water bunkers and with large radius tops on the water tanks.[1]

Beyer, Peacock

The second order of eight locomotives was delivered from Beyer, Peacock and Company in 1939. They were numbered in the range from NG109 to NG116.[1][2][3]

The third order was for a further seven locomotives in 1951, numbered in the range from NG125 to NG131, once again from Beyer, Peacock. These and the subsequent locomotives had welded water and coal bunkers and flat top water tanks with rounded top side edges.[1][2][3]

The fourth batch of seven locomotives, numbered in the range from NG137 to NG143, were the last steam locomotives to be built by Beyer, Peacock and were ordered and built to the specifications of the Tsumeb Copper Corporation in South West Africa (SWA). They were mechanically similar to the earlier and subsequent Class NG G16 locomotives, but with a revised coal and water carrying arrangement. These locomotives had an enlarged front water tank capacity, but carried no water in their rear bunkers, which consequently had an enlarged coal capacity. It was planned to attach a water tanker to the locomotive for use across the Namib desert in SWA, as was the practice with the Cape gauge Class GM and Class GMA Garratts in South Africa.[2][3]

However, while the locomotives were being built, the decision was made to convert all the SWA narrow gauge lines to Cape gauge. In terms of a prior agreement between the SAR and the Tsumeb Copper Corporation, the SAR would purchase any narrow gauge locomotives that would become redundant should the re-gauging of the SWA system take place. The new locomotives were therefore delivered directly to the SAR in 1958.[2]

With the shorter distances between watering points in South Africa, an auxiliary water tanker was never required on the Avontuur and Natal narrow gauge lines where they were placed in service.[2]

Hunslet-Taylor

The final order for eight locomotives in 1967, numbered in the range from NG149 to NG156, turned out to be the last new steam locomotives to be ordered by the SAR. Since no overseas manufacturers were available to supply them, they were built by Hunslet-Taylor in Germiston, Transvaal, using boilers supplied by their overseas principals, the Hunslet Engine Company. Built between 1967 and 1968, these locomotives had the same enlarged capacity front water tank as that of the Tsumeb group, but their rear bunkers were identical to those of the 1951 batch of locomotives, carrying both coal and water.[2][4]

Service

The Cockerill locomotives, numbers NG85 to NG88, remained in Natal for most of their service lives.[1][2]

The Beyer, Peacock locomotives ordered by the SAR, numbers NG109 to NG116 and NG125 to NG131, were shared more or less equally between the Natal and Avontuur lines.[1][2]

The seven Beyer, Peacock locomotives ordered by the Tsumeb Copper Corporation, numbers NG137 to NG143, were initially distributed between the Umzinto, Port Shepstone and Avontuur lines, but the three that went to the Langkloof were soon transferred to Natal as well.[1][2]

The Hunslet-Taylor locomotives, numbers NG149 to NG156, were placed in service on the Harding and Donnybrook branches in Natal in 1968.[1][2]

The end of SAR steam

When the lower section of the Avontuur line was dieselised with the arrival of the Class 91-000 diesel-electric locomotive in 1973, all the Class NG G16 locomotives that were still in service were transferred to various branches in Natal, where they remained until they were withdrawn from service. The Class 91-000 diesels and the remaining Class NG15 Kalaharis served the Langkloof together for some years, but by the mid-1980s road transport had triumphed over rail transport on the apple route as well and the SAR narrow gauge steam fleet was retired.[2]

Class NG G16A modification

When the four Natal narrow gauge systems were closed down by the SAR, the Weenen and Mid Illovo lines were lifted, but the Harding line was privatised as the Alfred County Railway (ACR), operating out of Port Shepstone.[1]

As part of their strategy to keep the railway competitive, two of the ACR’s Class NG G16 locomotives were rebuilt using technology similar to that used in the Class 26 Red Devil. The rebuilding incorporated a gas producing combustion system (GPCS), Lempor exhausts, an improved spark arrester, lightweight multi-ring articulated piston valves, improved valve events and improved mechanical lubrication. The two locomotives that received this treatment, number NG141 in 1989 and number NG155 in 1990, were reclassified to Class NG G16A.[6][7]

In comparative testing, number NG141 achieved a fuel saving of 25% compared to a standard Class NG G16 Garratt, a performance that was easily maintained in regular service. The cost of the work paid off financially within twelve months and led to a proposal to develop a Class NG G17, but that never materialised since the line’s farming produce traffic was gradually lost to road transport on the improving road network.[6][7][8]

Preservation

Since withdrawal from SAR service, some locomotives were sold into private hands and kept in operational condition, while others ended up in various degrees of preservation ranging across the spectrum from running order to staging to total abandonment. By 2012 at least three establishments still operated or were restoring ex SAR class NG G16 Garratts.[8]

Welsh Highland Railway

The Welsh Highland Railway in the United Kingdom owns four Class NG G16 locomotives, of which one has been used for spares to keep the other three running. These three locomotives, Cockerill-built number NG87 and Beyer, Peacock-built numbers NG138 and NG143, are kept in excellent condition by an establishment that exhibits great pride in its heritage.[8]

Sandstone Estates

The Sandstone Estates near Ficksburg in the Free State was home to a large number of Class NG G16 locomotives, either as the owners or as the custodian for locomotives belonging to individuals or other establishments. Three of their Class NG G16 locomotives are still being kept in pristine condition and are regularly run during the Estate’s annual events like the Cosmos Festival, Cherry Festival and others. These are Cockerill-built no. NG88, Beyer, Peacock-built no. NG113 and Hunslet-Taylor-built no. NG153.[8]

Puffing Billy Railway

The Puffing Billy Railway (PBR), located in the Dandenong Ranges east of Melbourne, Australia, began restoring Class NG G16 no. NG129 and regauging it to 2 ft 6 in (762 mm) as a backup for their Victorian Railways G class Garratt no. G42. Completion of no. NG129's restoration was planned to coincide with the next time that no. G42 was expected to be withdrawn for major maintenance. Faced with the need to manufacture a number of missing parts for no. NG129, the PBR also purchased no. NG127 and a container of spare parts in early 2012. It was expected that this would greatly simplify the restoration project and also give them a second almost-complete Class NG G16 which may also be restored in future.[9]

Distribution

The last known fate of all the Class NG G16 locomotives, as at January 2015, are shown in the table.[8]

South African Class NG G16 2-6-2+2-6-2 Locations

Illustration

The main picture and the following photographs offer views of the various models of the Class NG G16 locomotive.

References

  1. 1 2 3 4 5 6 7 8 9 Durrant, A E (1989). Twilight of South African Steam (1st ed.). Newton Abbott, London: David & Charles. pp. 126–127. ISBN 0715386387.
  2. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Paxton, Leith; Bourne, David (1985). Locomotives of the South African Railways (1st ed.). Cape Town: Struik. pp. 10–11, 107, 109–110. ISBN 0869772112.
  3. 1 2 3 4 Hamilton, Gavin N., The Garratt Locomotive - Garratt Locomotives produced by Beyer, Peacock, retrieved 10 November 2012
  4. 1 2 3 Hamilton, Gavin N., The Garratt Locomotive - Garratt Locomotives from Other Builders, retrieved 10 November 2012
  5. ↑ South African Railways and Harbours Locomotive Diagram Book, 2’0” & 3’6” Gauge Steam Locomotives, 15 August 1941, as amended
  6. 1 2 "The Ultimate Steam Page – P. Girdlestone". trainweb.org. Retrieved 2009-07-10.
  7. 1 2 3 "Alfred County Railway 2-6-2+2-6-2 NG G16A Garratts 141 & 155". martynbane.co.uk. Retrieved 2009-07-10.
  8. 1 2 3 4 5 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. pp. 32–33.
  9. 1 2 "Puffing Billy Monthly News, February 2012". Bill Russell. Retrieved 2012-01-30.
  10. 1 2 3 4 5 6 7 8 9 10 11 Payling, D (2012). Garratts & Kalaharis of the West Highland Railway (1st ed.). Porthmadog, Wales: The Ffestiniog & Welsh Highland Railways. pp. 129–130. ISBN 978 0 901848 10 9.
  11. ↑ Welsh Highland Railway news
  12. 1 2 Stars of Sandstone, Official Operating Programme for 12th - 21st April 2014 (stars 2014 - official operating programme-7.pdf)
  13. ↑ Exmoor Steam Railway and its history
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