South African Class 8B 4-8-0

In 1903, soon after its establishment, the Central South African Railways placed thirty Class 8-L2 4-8-0 Mastodon steam locomotives in service. In 1912, when they were assimilated into the South African Railways, they were renumbered and reclassified to Class 8B.^[3][5][7]

Manufacturers

Upon the establishment of the Central South African Railways (CSAR) in July 1902, soon after the end of the Second Freedom War, Chief Locomotive Superintendent P.A. Hyde became the custodian of a mixed bag of locomotives inherited from the Imperial Military Railways (IMR). These included locomotives that originated with the Selati Railway, the Nederlandsche Zuid-Afrikaansche Spoorwegmaatschappij (NZASM), the Pretoria-Pietersburg Railway (PPR) and the Oranje-Vrijstaat Gouwermentspoorwegen (OVGS).^[8]

The comparatively small number of serviceable locomotives that were immediately available for service, compounded by the poor condition of many of the original NZASM, PPR, Selati and OVGS locomotives as well as an expected post-war increase in traffic, led to an order for thirty Cape Class 8 4-8-0 steam locomotives from Neilson, Reid and Company.^[3]

They were built to the specifications of the Class 8 4-8-0 "Mastodon" type designed by H.M. Beatty, the Chief Locomotive Superintendent of the Cape Government Railways (CGR) from 1896 to 1910, and were the first locomotives to be ordered under the CSAR administration. Since, being equipped with Drummond tubes, they differed from the Class 8-L1, these locomotives were designated CSAR Class 8-L2.^[3][7]

While they were being built, Neilson, Reid amalgamated with Dübs and Company and Sharp, Stewart and Company to form the North British Locomotive Company (NBL). As a result, the first ten of these locomotives, numbered 441 to 450, were delivered as built by Neilson, Reid while the other twenty, numbered 451 to 470, were delivered as built by NBL, although all the NBL locomotives were also built at the Hyde Park shops of the former Neilson, Reid.^[2][3]

Class 8 sub-classes

In 1912, when these thirty locomotives were assimilated into the newly established South African Railways (SAR), they were renumbered 1132 to 1161 and reclassified to Class 8B.^[5][6][7]

These locomotives, together with the CSAR’s Class 8-L1 and 8-L3 4-8-0 Mastodon locomotives and all the CGR’s Class 8 2-8-0 Consolidations and 4-8-0 Mastodons, were grouped into ten different sub-classes by the SAR. The 4-8-0 locomotives became SAR Classes 8 and 8A to 8F and the 2-8-0 locomotives became Classes 8X to 8Z.^[4]

Modifications

Drummond tubes

When Hyde placed the order for these locomotives, he specified fireboxes equipped with Drummond water tubes. This involved the installation of cross-water tubes into the firebox, as featured on the London and South Western Railway’s T9 Class and L11 Class, in an attempt to increase the heat surface area of the water, albeit at the cost of increased boiler complexity.^[3]

On the as built Class 8-L2 locomotives, visible exterior evidence of the presence of Drummond tubes was two offset rectangular covers attached to the sides of the firebox just ahead of the cab.^[3]

The CGR had also experimented with Drummond tubes by modifying its Class 6 number 286 and found that the benefit in improved performance was minimal while the tubes were inclined to leak and were difficult to maintain. Like the CGR, the CSAR soon learned that the increase in steaming capacity was not sufficient to warrant the initial cost and increased maintenance involved. In the SAR era the tubes were gradually removed as the boilers required repairs, but the locomotives retained their Class 8B designation.^[3]

Superheating

During A.G. Watson’s term as the Chief Mechanical Engineer (CME) of the SAR from 1929 to 1936, many of the Class 8 to Class 8F locomotives were equipped with superheated boilers, larger bore cylinders and either inside or outside admission piston valves.^[4][7]

The outside admission locomotives had their cylinder bore increased from 18.5 inches (470 millimetres) to 19 inches (483 millimetres) and retained their existing SAR classifications, while the inside admission locomotives had their cylinder bore increased to 20 inches (508 millimetres) and were reclassified, with a "W" suffix added to their existing SAR classifications.^[4][7]

Of the Class 8B locomotives, nine were equipped with superheated boilers, 19 inches (483 millimetres) bore cylinders and outside admission piston valves, while retaining their Class 8B classification.^[4]

Six locomotives were equipped with superheated boilers, 20 inches (508 millimetres) bore cylinders and inside admission piston valves and were reclassified to Class 8BW.^[4]

The Class 8B and 8BW builders, works numbers, renumbering and superheating modifications are shown in the table.^[1][4][5]

Service

In SAR service, the 4-8-0 Class 8 family of locomotives served on every system in the country and in the 1920s became the mainstay of motive power on many branch lines. Their final days were spent in shunting service and by 1972 they were all withdrawn.^[7]

Gallery

The main picture is a scan of a circa 1935 post card showing an SAR Class 8B, ex CSAR Class 8-L2, banking at the Waterval Boven tunnel circa 1912.

See also

• South African Class 8 4-8-0
• South African Class 8A 4-8-0
• South African Class 8C 4-8-0
• South African Class 8D 4-8-0
• South African Class 8E 4-8-0
• South African Class 8F 4-8-0
• South African Class 8X 2-8-0
• South African Class 8Y 2-8-0
• South African Class 8Z 2-8-0
• Tender locomotive numbering and classification
• The 4-8-0 "Mastodon"
• List of South African locomotive classes

References

1. ^ ^{a b c} Neilson, Reid works list, compiled by Austrian locomotive historian Bernhard Schmeiser
2. ^ ^{a b c} North British Locomotive Company works list, compiled by Austrian locomotive historian Bernhard Schmeiser
3. ^ ^{a b c d e f g h i} Holland, D.F. (1971). Steam Locomotives of the South African Railways, Volume 1: 1859-1910 (1st ed.). Newton Abbott, Devon: David & Charles. pp. 56, 127. ISBN 0715353829. 
4. ^ ^{a b c d e f g} South African Railways and Harbours Locomotive Diagram Book, 2’0” & 3’6” Gauge Steam Locomotives, 15 August 1941, as amended
5. ^ ^{a b c d} Classification of S.A.R. Engines with Renumbering Lists, issued by the Chief Mechanical Engineer’s Office, Pretoria, January 1912, pp. 8, 12, 15, 41 (Reprinted in April 1987 by SATS Museum, R.3125-6/9/11-1000)
6. ^ ^{a b} Holland, D.F. (1972). Steam Locomotives of the South African Railways, Volume 2: 1910-1955 (1st ed.). Newton Abbott, Devon: David & Charles. p. 139. ISBN 0715354272. 
7. ^ ^{a b c d e f g} Paxton, Leith; Bourne, David (1985). Locomotives of the South African Railways (1st ed.). Cape Town: Struik. pp. 48-49. ISBN 0869772112. 
8. ^ Durrant, A E (1989). Twilight of South African Steam (1st ed.). Newton Abbott, London: David & Charles. p. 8. ISBN 0715386387.