| South African Class NG G16 2-6-2+2-6-2 | |
|---|---|
| NG G16 113 at Sandstone Estates, 9 April 2006 | |
| 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)[1] Beyer, Peacock 6919-6926 (1939), 7426-7432 (1951), 7862-7868 (1958)[2] Hunslet-Taylor 3894-3901 (1967-1968)[1] |
| Model | Class NG G16 |
| Build date | 1937-1968 |
| Total produced | 34 |
| 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: 43 ft 3 in (13.183 m) Engine units: 6 ft 3 in (1.905 m) coupled 13 ft 10.5 in (4.229 m) total |
| Length | 48 ft 3.25 in (14.713 m) |
| Width | 7 ft (2.134 m) |
| Height | 10 ft 4 in (3.150 m) |
| Frame | Bar frame, 23 ft 9 in (7.239 m) 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 |
| Weight on drivers | All but 137-143: 39.25 long tons (39.9 t) 137-143: 40.125 long tons (40.8 t) |
| Locomotive 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 capacity | 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 |
| 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) ext dia 15 tubes 5.5 in (140 mm) ext 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[3] |
| Career | South African Railways |
| Class | Class NG G16 |
| Number in class | 34 |
| Number | 85-88, 109-116, 125-131, 137-143, 149-156 |
| Delivered | 1937-1968 |
| First run | 1937 |
| Disposition | Retired |
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 wheel arrangement in service on the Avontuur Railway and on the Natal narrow gauge lines.[4][5]
Contents |
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 locomotives would be of the same design. Altogether thirty-four more 2-6-2+2-6-2 locomotives were built, spread over five orders from three manufacturers over a span of thirty-one years.[4]
In 1937 Société Anonyme John Cockerill of Seraing in Belgium delivered four new 2-6-2+2-6-2 locomotives, numbered 85 to 88, 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.[1][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.[5]
The second order of eight locomotives was delivered from Beyer, Peacock and Company in 1939 and were numbered 109 to 116.[2][4][5]
The third order was for a further seven locomotives in 1951, numbered 125 to 131, once again from Beyer, Peacock. These and the subsequent locomotives had welded water and coal bunkers and flat tops between the rounded top side edges on the water bunkers.[2][4][5]
The fourth batch of seven locomotives, numbered 137 to 143, 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 bunker 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 GMAM Garratts in South Africa.[2][4]
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.[4]
With the shorter distances between watering points in South Africa, an auxiliary water tanker was never required on the Avontuur and Natal lines where they were placed in service.[4]
The final order for eight locomotives in 1967, numbers 149 to 156, 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 bunker 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.[1][4]
The Cockerill locomotives, numbers 85 to 88, remained in Natal for most of their service lives.[4][5]
The Beyer, Peacock locomotives ordered by the SAR, numbers 109 to 116 and 125 to 131, were shared more or less equally between the Natal and Avontuur lines.[4][5]
The seven Beyer, Peacock locomotives ordered by the Tsumeb Copper Corporation, numbers 137 to 143, 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.[4][5]
The Hunslet-Taylor locomotives, numbers 149 to 156, were placed in service on the Harding and Donnybrook branches in Natal in 1968.[4][5]
When the four Natal narrow gauge systems were closed down by the SAR, the Weenen and Mid Illovo lines were torn up, but the Harding line was privatised as the Alfred County Railway (ACR), operating out of Port Shepstone.[5]
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 141 in 1989 and number 155 in 1990, were reclassified to Class NG G16A.[6][7]
In comparative testing, number 141 achieved a fuel saving of 25% compared to a standard Class NG G16 Garratt, 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 realised since the line’s farming produce traffic was gradually lost to road transport on the improving road network.[6][7][8]
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 narrow gauge steam fleet was retired.[4]
Since withdrawal from SAR service, some locomotives were sold into private hands and are being 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. At least two establishments own ex SAR class NG G16 Garratts that are being kept in excellent running order.[8]
The Welsh Highland Railway in the United Kingdom owns four Class NG G16 locomotives, of which one is being used for spares to keep the other three running. These three locomotives, Cockerill built number 87 and Beyer, Peacock built numbers 138 and 143, are kept in excellent condition by an establishment that exhibits great pride in their heritage.[8]
The Sandstone Estates near Ficksburg in the Free State is 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. Two of their Class NG G16 locomotives are being kept in pristine condition and regularly run during the Estate’s annual events like the Cosmos Festival, Cherry Festival and others. These are Beyer, Peacock built number 113 and Hunslet-Taylor built number 153.[8]
The known fate of all the Class NG G16 locomotives are shown in the table.[8]
The main picture shows Beyer, Peacock built number 113 at Sandstone Estates near Ficksburg on 9 April 2006.
|
||||||||||||||||||||||||||||||||||||
