| South African Classes 16 & 16R4-6-2 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Class 16 no. 800, Braamfontein, c. 1930 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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TheSouth African Railways Class 16 4-6-2 of 1914 was a steam locomotive.
In 1914, the South African Railways placed twelve Class 16 steam locomotives with a4-6-2 Pacific type wheel arrangement in passenger train service.[1][2][3]
The Class 16 4-6-2 Pacific type passenger locomotive was designed by D.A. Hendrie, Chief Mechanical Engineer (CME) of the South African Railways (SAR) from 1910 to 1922. It was built by theNorth British Locomotive Company inGlasgow, Scotland, who delivered twelve locomotives in 1914, numbered in the range from 790 to 801.[1][2][3][4]

The design of the Class 16 closely followed that of Hendrie'sClass 15 4-8-2 Mountain type which was introduced at the same time from the same builders and many parts were made interchangeable.[1][3]
The cylinders were arranged outside the plate frames, with the piston valves above the cylinders and actuated byWalschaerts valve gear. The boilers were equipped with superheaters and hadBelpaire fireboxes. The engines were delivered new withType MP1 tenders with a 10 long tons (10.2 tonnes) coal capacity and a 4,250 imperial gallons (19,300 litres) water capacity.[1][2][3][5][6]
When it was built in 1914, the Class 16 was considered to be a very large and powerful express locomotive, even when compared to British locomotives which were built to run on4 feet8+1⁄2 inches (1,435 millimetres) broad gauge. As built, with 60 inches (1,524 millimetres) diameter coupled wheels, the ratio of wheel diameter to rail gauge was the same as that of a broad gauge locomotive with 81 inches (2,057 millimetres) diameter coupled wheels. Their tractive effort of 29,890 pounds-force (133.0 kilonewtons) at 75% boiler pressure exceeded the 27,800 pounds-force (124 kilonewtons) at 85% boiler pressure ofChurchward'sThe Great Bear Pacific on theGreat Western Railway and equalled, also at 85% boiler pressure, that ofGresley's laterGreat Northern Pacifics. This made the Class 16 the most powerful express passenger locomotive design yet to have been built inGreat Britain at the time.[7]
During the 1930s, many serving locomotives were reboilered with a standard boiler type designed by A.G. Watson, CME of the SAR from 1929 to 1936, as part of his standardisation policy. Such Watson Standard reboilered locomotives were reclassified by adding an "R" suffix to their classification.[3][5][6]

Eventually all twelve Class 16 locomotives were reboilered withWatson Standard no. 2B boilers and reclassified to Class 16R. Early conversions were equipped with copper and later conversions with steel fireboxes. In the process, they were also equipped with Watson cabs with their distinctive slanted fronts, compared to the conventional vertical fronts of their original cabs.[3][5][6]
Their original Belpaire boilers were fitted withRamsbottom safety valves, while the Watson Standard boiler was fitted withPop safety valves. An obvious visual difference between an original and a Watson Standard reboilered locomotive is usually a rectangular regulator cover, just to the rear of the chimney on the reboilered locomotive. In the case of the Class 16 and Class 16R locomotives, two even more obvious differences are the Watson cab and the absence of the Belpaire firebox hump between the cab and boiler on the reboilered locomotives.[3][5][6]
The Class 16 was intended for fast passenger trains in Transvaal, the Orange Free State and the upper sections of Natal where the gradients were not as severe. They were placed in suburban passenger service, working betweenPretoria andJohannesburg, and in mainline service on the section fromJohannesburg toVolksrust on the line to Natal. In later years, after being withdrawn from mainline passenger service, many of these locomotives remained employed in suburban passenger working and shunting service.[1][2][3][7]
| Number | Works nmr | THF / Private | Leaselend / Owner | Current Location | Outside South Africa | ? |
|---|---|---|---|---|---|---|
| 794 | THF | Krugersdorp Locomotive Depot |
The main picture shows Class 16 no. 800 at Braamfontein c. 1930, as built with a Belpaire firebox and Type MP1 tender, on interurban service with a destination board for Pretoria below its headlight.