| South African Class NG2 0-4-2T | |
|---|---|
| Class NG2 as built with a saddle tank | |
| Power type | Steam |
| Designer | Dickson Manufacturing Company |
| Builder | Dickson Manufacturing Company |
| Serial number | 978 & 1019 |
| Build date | 1897 & 1898 |
| Total produced | 2 |
| Rebuilder | South African Railways |
| Number rebuilt | 2 |
| Configuration | 0-4-2ST as built, 0-4-2T rebuilt |
| Gauge | 600 mm (23.62 in) |
| Driver diameter | 24.5 in (622 mm) |
| Trailing wheel diameter |
20.5 in (521 mm) |
| Wheelbase | 10 ft 4.5 in (3.162 m) total 4 ft (1.219 m) coupled |
| Length | 18 ft 10 in (5.740 m) |
| Width | 6 ft 3.5 in (1.918 m) |
| Height | 8 ft 7 in (2.616 m) over cab |
| Frame | Bar frame |
| Axle load | 4 long tons (4.1 t) per driver |
| Weight on drivers | 8 long tons (8.1 t) |
| Locomotive weight | 22,000 lb (10.0 t) empty 11 long tons (11.2 t) w/o |
| Fuel type | Coal |
| Fuel capacity | 21.5 long cwt (1,090 kg) |
| Water capacity | 200 imp gal (910 l) as built |
| Boiler | 2 ft 2.875 in (0.683 m) int dia 6 ft 8.5 in (2.045 m) int length 3 ft 8.25 in (1.124 m) pitch |
| Boiler pressure | 130 psi (896 kPa) |
| Firegrate area | 5.83 sq ft (0.542 m2) |
| Heating surface: Tubes |
60 tubes 1.5 in (38.1 mm) ext dia 158 sq ft (14.679 m2) |
| Heating surface: Firebox |
33 sq ft (3.066 m2) |
| Heating surface: Total |
191 sq ft (17.744 m2) |
| Cylinders | Two |
| Cylinder size | 7 in (178 mm) bore 10 in (254 mm) stroke |
| Valve gear | Stephenson |
| Tractive effort | 1,950 lbf (8.7 kN) at 75% boiler pressure[1] |
| Career | Rand Mines Limited South African Railways |
| Class | Class NG2 |
| Number in class | 2 |
| Number | NG93-NG94 |
| Delivered | 1897 & 1898 |
| First run | 1897 |
| Withdrawn | 1936 |
| Disposition | Retired |
Between 1897 and 1901 Arthur Koppel, acting as agents, imported a number of Dickson built 0-4-2ST narrow gauge saddle tank steam locomotives to mines on the Witwatersrand. In 1915, when an urgent need arose for additional locomotives in German South West Africa during World War I, two of the 0-4-2ST locomotives were purchased second-hand by the South African Railways for use in that territory. They were later classified as Class NG2.[2][3]
Contents |
Between 1897 and 1901 several 0-4-2ST narrow gauge saddle tank steam locomotives, built by Dickson Manufacturing Company of Scranton in Pennsylvania shortly before it merged with seven other manufacturing firms to form the American Locomotive Company (ALCO) in 1901, were delivered to various gold mines on the Witwatersrand by Arthur Koppel, acting as importing agents.[2][3]
In 1915, while the military campaign was being waged against German forces in Deutsch-Südwest-Afrika (DSWA, now Namibia) during World War I, an urgent need arose for additional locomotives for use on the narrow gauge lines in that territory. The South African Railways (SAR) therefore bought two of these Dickson built 0-4-2ST locomotives second-hand, numbered them NG93 and NG94 and placed them in service in DSWA.[3]
The identity of these locomotives is difficult to prove, but the SAR diagram book for the Class NG2 gives dimensions that limit the possibilities to only three of the known Koppel imports. Two of these, Dickson works numbers 978 of 1897 and 1019 of 1898, had been delivered to the Lancaster Gold Mine in Roodepoort. That mine closed in June 1913, the company being wound up in early 1915. It therefore seems a good possibility that it were these two locomotives that the SAR bought for service in DSWA.[1][2]
A third locomotive with the same dimensions for which no ownership history is known was Dickson works number 1102 of 1899. It is possible, but unproven, that this locomotive also went to Lancaster Gold Mine since it was of identical dimensions as the other two.[2]
The locomotives had bar frames and used Stephenson valve gear. Although they were eventually classified as two foot narrow gauge locomotives along with the rest of the South African 2 feet (610 millimetres) gauge locomotive fleet, they were actually constructed to a 600 millimetres (23.62 inches) gauge.[4]
Historically, the actual two feet narrow gauge rail spacing depended on whether or not the track was laid by a metricised country. German built narrow gauge lines in DSWA were therefore 600 millimetres (23.62 inches) gauge, while those in South Africa, built to Imperial standards, were 610 millimetres (24 inches) gauge.[5]
In practice, however, the two gauges are still being treated as one and the same by the British Military. The same applied in South Africa, being part of the British Empire at the time. The 10 millimetres (0.39 inches) difference was considered as insignificant and narrow gauge locomotives regularly migrated between the lines laid to German standards in South West Africa (SWA) and those laid to Imperial standards in South Africa.[5]
The two locomotives remained in SWA after the war. In 1920 they were both reboilered by the SAR, using boilers supplied by Henschel and Son, and in the process they lost their saddle tanks. Since this modification effectively converted them to tankless tank locomotives, they were equipped with timber bodied two axle tenders to carry their water and additional coal.[2][3][4]
A system of grouping narrow gauge locomotives into classes was only introduced on the SAR somewhere between 1928 and 1930. At that point, the two locomotives were classified as Class NG2.[1]
The Class NG2 locomotives spent their last working years on the SAR working at the Usakos workshops in SWA, until they were withdrawn from service in 1936. NG94 was sold to Igusi Timbers in Rhodesia and remained in service there until circa 1961. NG93 was sold to the Zebediela citrus estates in northern Transvaal in 1937, where it was finally withdrawn from service by 1943.[2][3]
The main picture shows the Class NG2 as built with a saddle tank.
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