| South African Class NG G12 2-6-2+2-6-2 | |
|---|---|
| NG G12 57, circa 1930 | |
| Power type | Steam |
| Designer | Beyer, Peacock and Company |
| Builder | Société Franco-Belge |
| Serial number | BP 6365-6366, FB 2506-2507[1][2] |
| Model | Class NG G12 |
| Build date | 1927 |
| Total produced | 2 |
| Configuration | 2-6-2+2-6-2 "Double Prairie" Garratt |
| Gauge | 2 ft (610 mm) |
| Leading wheel diameter |
21 in (533 mm) |
| Driver diameter | 30 in (762 mm) |
| Trailing wheel diameter |
21 in (533 mm) |
| Wheelbase | Total: 40 ft (12.192 m) Engine units: 5 ft 9 in (1.753 m) coupled 12 ft 7.5 in (3.848 m) total |
| Length | 45 ft 10 in (13.970 m) |
| Height | 10 ft (3.048 m) |
| Frame | Plate frame, 21 ft (6.401 m) between pivot centres |
| Axle load | 3.75 long tons (3.8 t) per driver |
| Weight on drivers | 22.5 long tons (22.9 t) |
| Locomotive weight | 36 long tons (36.6 t) |
| Fuel type | Coal |
| Fuel capacity | 2 long tons (2.0 t) |
| Water capacity | 800 imp gal (3,600 l) front 200 imp gal (910 l) rear |
| Boiler | 3 ft 6.375 in (1.076 m) int dia 8 ft 6 in (2.591 m) int length 5 ft 3 in (1.600 m) pitch |
| Boiler pressure | 180 psi (1,240 kPa) |
| Firegrate area | 10.5 sq ft (0.975 m2) |
| Heating surface: Tubes |
73 tubes 1.75 in (44.5 mm) ext dia 10 tubes 5.25 in (133 mm) ext dia 378.5 sq ft (35.164 m2) |
| Heating surface: Firebox |
45 sq ft (4.181 m2) |
| Heating surface: Total |
423.5 sq ft (39.344 m2) |
| Superheater area | 97.5 sq ft (9.058 m2) |
| Cylinders | Four |
| Cylinder size | 8.5 in (216 mm) bore 16 in (406 mm) stroke |
| Valve gear | Walschaerts |
| Tractive effort | 10,400 lbf (46.3 kN) at 75% boiler pressure[3] |
| Career | South African Railways |
| Class | Class NG G12 |
| Number in class | 2 |
| Number | 56-57 |
| Delivered | 1927 |
| First run | 1927 |
| Withdrawn | 1952 |
In 1927 the South African Railways placed two Class NG G12 Garratt articulated steam locomotives with a 2-6-2+2-6-2 wheel arrangement in service. They were the smallest Garratt locomotives to see service in South Africa.[3][4]
Contents |
The South African Railways (SAR) placed orders for two light weight narrow gauge Garratt locomotives with a 2-6-2+2-6-2 wheel arrangement with Beyer, Peacock and Company in 1927. Beyer, Peacock sub-contracted their construction and the two locomotives were delivered by the Belgian locomotive builders Société Franco-Belge later in 1927. They were allocated separate works numbers by Beyer, Peacock as well as Franco-Belge, and were numbered NG56 and NG57 upon delivery.[1][2][3][4]
The locomotives were superheated, with outside plate frames, Walschaerts valve gear and round top fireboxes. Designed for light 20 pounds per yard (9.9 kilograms per metre) rail, their lightness of construction made them popular with the fitters who had to maintain them.[4]
The system of grouping narrow gauge locomotives into classes was only adopted by the SAR somewhere between 1928 and 1930 and at that point these two Garratt locomotives were classified as Class NG G12, with the letters "NG" indicating narrow gauge and the "G" prefix to the classification number identifying it as a Garratt locomotive.[3][4]
The Class NG G12 was obtained for utilisation on the new narrow gauge lines from Fort Beaufort to Seymour and from Upington to Kakamas, since it had become obvious that the Class NG6 Lawleys that had been used during the construction of these lines would not be able to cope with the expected daily traffic once the lines were opened.[4]
Upon arrival, the two locomotives were first put to work in South West Africa (SWA) for a trial period, after which NG56 was assigned to Upington and NG57 to Fort Beaufort.[4]
While they both mostly remained with their assigned depots, they were at times temporarily assigned to branches in other areas of the country to assist with seasonal demands on those branches. In 1940, when the Seymour branch was regauged to Cape gauge, NG57 was also assigned to the Kakamas branch. Both remained there until 1949, when the Kakamas line was also widened to Cape Gauge and they were returned to SWA for a brief period. From there, NG56 was allocated to Port Shepstone in Natal and NG57 to Humewood Road in Port Elizabeth, where they remained until both were withdrawn from service in 1952.[4]
Both locomotives were subsequently sold to the Rustenburg Platinum Mines, number 56 in 1952 and number 57 in 1953, where they were renumbered 5 and 6 respectively. They were both scrapped in 1959.[5]
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