South African Class 10B 4-6-2
Encyclopedia
In March 1910 the Central South African Railways
Central South African Railways
From 1902 to 1904, the area of power of Lieutenant-Colonel Sir Percy Girouard later also included the lines of The Netherlands-South African Railway Company; together this dominion covered all lines in the Transvaal that belonged to NZASM ....

 placed ten Class 10-2 steam locomotive
Steam locomotive
A steam locomotive is a railway locomotive that produces its power through a steam engine. These locomotives are fueled by burning some combustible material, usually coal, wood or oil, to produce steam in a boiler, which drives the steam engine...

s with a 4-6-2
4-6-2
4-6-2, in the Whyte notation for the classification of steam locomotives, represents the wheel arrangement of four leading wheels on two axles , six powered and coupled driving wheels on three axles, and two trailing wheels on one axle .These locomotives are also known as Pacifics...

 Pacific wheel arrangement in service, of which five were built with and five without superheaters. In 1912, when the five superheated locomotives were assimilated into the South African Railways, they were renumbered and reclassified to Class 10B. In 1912 the South African Railways placed five more Class 10B locomotives in service.

Manufacturers

Ten heavy 4-6-2 “Pacific” type passenger locomotives, designed by Central South African Railways (CSAR) Chief Mechanical Engineer (CME) G.G. Elliot and based on the Class 10 design of his predecessor, CSAR Chief Locomotive Superintendent P.A. Hyde, were ordered from the North British Locomotive Company
North British Locomotive Company
The North British Locomotive Company was created in 1903 through the merger of three Glasgow locomotive manufacturing companies; Sharp Stewart and Company , Neilson, Reid and Company and Dübs and Company , creating the largest locomotive manufacturing company in Europe.Its main factories were...

 (NBL) and delivered in 1910. They had Belpaire firebox
Belpaire firebox
The Belpaire firebox is a type of firebox used on steam locomotives. It was invented by Alfred Belpaire of Belgium. It has a greater surface area at the top of the firebox, improving heat transfer and steam production...

es and Walschaerts valve gear and were delivered in two variants, five of them using saturated steam while the rest were superheated with Schmidt type superheaters. They were all classified as Class 10-2 by the CSAR, numbered 665 to 674, and entered service in March 1910.

When they were assimilated into the newly established South African Railways (SAR) in 1912, the five saturated locomotives, numbers 665 to 669, were reclassified as Class 10A
South African Class 10A 4-6-2
In 1910 the Central South African Railways placed ten Class 10-2 4-6-2 Pacific steam locomotives in service, of which five were built with and five without superheaters...

 while the five superheated locomotives, numbers 670 to 674, were designated Class 10B and were renumbered 752 to 756.

In 1911 the CSAR ordered a further five superheated Class 10B locomotives from Beyer, Peacock and Company
Beyer, Peacock and Company
Beyer, Peacock and Company was an English railway Locomotive manufacturer with a factory in Gorton, Manchester. Founded by Charles Beyer and Richard Peacock, it traded from 1854 until 1966...

. They were delivered to the SAR in 1912 and numbered 757 to 761, with their running numbers out of sequence with their builder’s works numbers.

Characteristics

These locomotives were similar to the CSAR Class 10, except that their boilers were arranged 7.5 inches (190.5 mm) further forwards and their firebox throats and back plates were sloped instead of being vertical. Like the Class 10
South African Class 10 4-6-2
In 1904 the Central South African Railways placed fifteen Class 10 steam locomotives with a 4-6-2 Pacific wheel arrangement in service. In 1912, when they were assimilated into the South African Railways, they were renumbered but retained their Class 10 classification.-Manufacturer:Fifteen 4-6-2...

, they had 62 inches (1,574.8 mm) drivers, the largest yet used in South Africa.

While the Class 10 had outside admission valves, the Class 10B used inside admission piston valves. The valve gear was reversed by means of a vertical steam reversing engine placed on the right-hand running board in line with the steam dome. Two Trevithick
Richard Trevithick
Richard Trevithick was a British inventor and mining engineer from Cornwall. His most significant success was the high pressure steam engine and he also built the first full-scale working railway steam locomotive...

 exhaust steam feedwater heaters were mounted on the running boards on either side of the smokebox, and a Weir’s feedwater pump was mounted on the left-hand side of the firebox. The feedwater heaters and the feedwater pump were removed after a few years since the feedwater heaters proved to be troublesome.

Watson standard boilers

During the 1930s many serving locomotives were reboilered with a standard boiler type designed by then CME A.G. Watson as part of his standardisation policy. Such Watson Standard reboilered locomotives were reclassified by adding an "R" suffix to their classification.

Five of the Class 10B locomotives were eventually reboilered with Watson Standard no. 1 boilers and reclassified to Class 10BR.

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 10BR locomotives an even more obvious visual difference was the absence of the Belpaire firebox hump between the cab and boiler on the reboilered locomotives.

The table displays the locomotive builders, works numbers, CSAR to SAR renumbering and the Watson Standard boiler reclassification for the Class 10B and 10BR locomotives.

Service

The Class 10B was placed in service hauling passenger trains out of Johannesburg. Most of their working lives were, however, spent on the Cape Midlands system, where they were used on the main line out of Port Elizabeth. Two of them worked as station pilots at Kimberley, but in 1960 they joined the rest of the Class that were by then working the suburban between Port Elizabeth and Uitenhage.

In later years they also served on the Reef’s suburban routes while a few were used in the same service around Cape Town, until they were eventually relegated to shunting work. They were scrapped in 1974.

Gallery

The main picture shows CSAR Class 10-2 674, later SAR Class 10B 756 and eventually Class 10BR, as delivered with feedwater heaters.


See also

  • South African Class 10 4-6-2
    South African Class 10 4-6-2
    In 1904 the Central South African Railways placed fifteen Class 10 steam locomotives with a 4-6-2 Pacific wheel arrangement in service. In 1912, when they were assimilated into the South African Railways, they were renumbered but retained their Class 10 classification.-Manufacturer:Fifteen 4-6-2...

  • South African Class 10A 4-6-2
    South African Class 10A 4-6-2
    In 1910 the Central South African Railways placed ten Class 10-2 4-6-2 Pacific steam locomotives in service, of which five were built with and five without superheaters...

  • South African Class 10C 4-6-2
    South African Class 10C 4-6-2
    In 1910 the Central South African Railways placed twelve Class 10-C 4-6-2 Pacific steam locomotives in service. When the South African Railways was established in 1912, these locomotives were renumbered and reclassified to Class 10C.-Manufacturer:...

  • South African Class 10D 4-6-2
    South African Class 10D 4-6-2
    In 1910 the Central South African Railways placed one American built Class 10 4-6-2 Pacific steam locomotive in service. When the South African Railways was established in 1912, this locomotive was renumbered and reclassified to the sole Class 10D....

  • Tender locomotive numbering and classification
  • Watson Standard boilers
  • The 4-6-2 "Pacific"
  • List of South African locomotive classes
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