South African Class NG5 2-8-2
| Company type | Steam locomotive |
|---|---|
| Industry | Railway |
| Founded | 1922 |
| Headquarters | South West Africa (now Namibia) |
| Products | Narrow-gauge steam locomotives |
South African Railways Class NG5 2-8-2 Narrow-Gauge Steam Locomotive
The Class NG5 2-8-2 steam locomotives were introduced by the South African Railways in 1922 as a series of narrow-gauge engines.
That year, six locomotives featuring a Mikado wheel configuration (2-8-2) were commissioned for operation on the Otavi Railway located in South West Africa. These locomotives were later assigned the Class NG5 designation when the narrow-gauge engines were systematically classified between 1928 and 1930.
Manufacturer
In 1921, six narrow-gauge 2-8-2 steam engines were produced for the South African Railways (SAR) by the German company Henschel and Son. These units were constructed following the design blueprint of the earlier three Class Hd locomotives, originally built in 1912 for the German authorities in German South West Africa (GSWA) to be leased to the Otavi Mining and Railway Company. The locomotives, assigned numbers NG71 through NG76, were delivered the following year, in 1922.
Characteristics
Sharing many features with the preceding Class Hd, these locomotives were superheated and utilized Walschaerts valve gear along with outside plate frames. However, they differed in their boiler design; although retaining identical dimensions, the tube configuration was altered, resulting in a marginally decreased overall heating surface.
Consistent with SAR standards at that time, these engines were equipped with vacuum train brakes rather than the air brakes found on the Class Hd. Notably, they featured slide valves—a rarity for superheated locomotives—in contrast to the piston valves used on their predecessors. Initially, sandboxes were positioned atop the boiler between the chimney and steam dome.
Their leading and trailing carrying wheels, fixed rigidly yet designed as radial axles, allowed lateral movement relative to the locomotive frame since there were no separate bogie trucks. This arrangement, as with the Class Hd, led to a rigid wheelbase measuring 17 feet 11⁄16 inch (5,199 millimetres), despite the leading wheels being set behind rather than ahead of the cylinders.
Classification
During operation, these six locomotives were pooled together with the three Class Hd engines. The SAR only introduced a formal classification system for narrow-gauge locomotives between 1928 and 1930. At that time, both groups—the six newer locomotives and the three Class Hd units—were collectively classified as Class NG5.
Service
Commissioned in 1922, the Class NG5 engines served exclusively on the 352-mile-long (566-kilometre) narrow-gauge route stretching from Swakopmund on the Atlantic coast through to Tsumeb and Grootfontein within South West Africa (SWA). Their entire operational lifespan was spent in SWA except for a short trial period when one unit was transferred to the Avontuur Railway in the Eastern Cape. This locomotive proved unsuitable for the tighter curves of the Langkloof, jamming despite having one set of flangeless driving wheels, leading to its swift return to SWA.
All six of these 1922-built Class NG5 locomotives were retired when SWA’s narrow-gauge lines were converted to Cape gauge in 1960. Due to their incompatibility with routes like Langkloof, they were all scrapped by 1962.
Preservation
Although every unit of the Class NG5 was ultimately dismantled, two locomotives from the related Class Hd have been conserved and are displayed as static exhibits in Otjiwarongo and Usakos, respectively.