South African Class 8E 4-8-0
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CGR 8th Class no. 814, SAR Class 8E no. 1231, c. 1950 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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| As built, the leading coupled axle had flangeless wheels | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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The South African Railways Class 8E 4-8-0 of 1903 was a steam locomotive from the pre-Union era in the Cape of Good Hope.
In 1903, at the same time that the Cape Government Railways ordered its second batch of thirty-eight 8th Class 4-8-0 Mastodon type steam locomotives, four additional experimental locomotives of the same class were ordered, built to modified specifications to accommodate a larger firegrate area. In 1912, when these four locomotives were assimilated into the South African Railways, they were renumbered and designated Class 8E.[1][2][3]
Manufacture
Evolution
The first Cape Government Railways (CGR) 8th Class locomotive was a 2-8-0 Consolidation type, designed by H.M. Beatty, the CGR's Chief Locomotive Superintendent from 1896 to 1910. These locomotives were later to become the South African Railways (SAR) Class 8X. While these first Schenectady- and ALCO-built 2-8-0 locomotives were being subjected to exhaustive testing on all types of traffic and under varying conditions, some trouble was experienced with the leading two-wheeled pony truck and, when designs were prepared at Salt River for a later order for more locomotives, the pony truck was replaced with a four-wheeled bogie, which resulted in the CGR's 4-8-0 Mastodon type 8th Class.[1]
In spite of the difference in wheel arrangements, the CGR's 2-8-0 Consolidations and post-7th Class 4-8-0 Mastodons were all grouped together as the 8th Class.[3]
Design
In 1902, when a second batch of thirty-eight 8th Class 4-8-0 locomotives was ordered, later to become the Class 8D on the SAR, an additional four engines were ordered. These were of an experimental design, to be built to modified specifications.[1][3]
Beatty believed that, while the earlier 8th Class locomotives (later the SAR Class 8) steamed well, they would steam even better if they had a larger firegrate area. He was hampered by the fact that the firebox wrapper plates had to fit between the rearmost coupled wheels. The result was that the greatest inside width obtainable on a firebox which was arranged between the wheels of a Cape gauge locomotive, was 27 1⁄2 inches (698 millimetres). He overcame this by designing an 8th Class locomotive with a deep curve in the foundation ring, or mud ring, to clear the intermediate coupled wheels, and a steep slope towards the rear to clear the trailing wheels. In the process he was able to increase the firegrate area from 21 to 27.5 square feet (1.951 to 2.555 square metres).[1][3][4]
Builders
The locomotives were ordered from Neilson, Reid and Company and delivered in 1903. They were delivered with Type XE1 tenders, numbered in the range from 813 to 816 and allocated to the Western System of the CGR.[1][3][5]
Class 8 sub-classes
When the Union of South Africa was established on 31 May 1910, the three Colonial government railways (CGR, Natal Government Railways and Central South African Railways) were united under a single administration to control and administer the railways, ports and harbours of the Union. Although the South African Railways and Harbours came into existence in 1910, the actual classification and renumbering of all the rolling stock of the three constituent railways required careful planning and was only implemented with effect from 1 January 1912.[2][6]
These locomotives, together with the rest of the CGR's fleet of 8th Class 2-8-0 Consolidations and 8th Class 4-8-0 Mastodons, plus the Classes 8-L1 to 8-L3 4-8-0 Mastodon locomotives from the Central South African Railways, were grouped into ten different sub-classes by the SAR. The 4-8-0 locomotives became SAR Classes 8 and 8A to 8F, while the 2-8-0 locomotives became Classes 8X to 8Z.[7]
In 1912, these four locomotives were renumbered in the range from 1230 to 1233 and reclassified to Class 8E on the SAR.[2][3][8]
Modifications
Reboilering
With no appreciable gain obtained in steaming capacity, the enlarged grate area on these experimental locomotives did not come up to expectations. Since the fireboxes began to have problems with cracks and leaking rivets soon after the locomotives were placed in service, the experimental boilers and fireboxes were soon replaced with standard 8th Class boilers and fireboxes.[1][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. The outside admission valve locomotives had their cylinder bore increased from 18 1⁄2 to 19 inches (470 to 483 millimetres) and retained their existing SAR classifications, while the inside admission valve locomotives had their cylinder bore increased to 20 inches (508 millimetres) and were reclassified by having a "W" suffix added to their existing SAR classifications.[3][7]
Of the four Class 8E locomotives, numbers 1232 and 1233 were equipped with superheated boilers, 19 inches (483 millimetres) bore cylinders and outside admission piston valves, while retaining their Class 8E classification.[7]
Service
In SAR service, the 4-8-0 Class 8 family of locomotives worked on every system in the country and, during the 1920s, became the mainstay of motive power on many branchlines. Their final days were spent in shunting service. By 1972, they were all withdrawn from service.[3]
References
- 1 2 3 4 5 6 Holland, D.F. (1971). Steam Locomotives of the South African Railways, Volume 1: 1859-1910 (1st ed.). Newton Abbott, Devon: David & Charles. p. 64. ISBN 978-0-7153-5382-0.
- 1 2 3 Classification of S.A.R. Engines with Renumbering Lists, issued by the Chief Mechanical Engineer's Office, Pretoria, January 1912, pp. 9, 12, 15, 43 (Reprinted in April 1987 by SATS Museum, R.3125-6/9/11-1000)
- 1 2 3 4 5 6 7 8 9 Paxton, Leith; Bourne, David (1985). Locomotives of the South African Railways (1st ed.). Cape Town: Struik. p. 49. ISBN 0869772112.
- ↑ Espitalier, T.J.; Day, W.A.J. (1944). The Locomotive in South Africa - A Brief History of Railway Development. Chapter II - The Cape Government Railways (Continued). South African Railways and Harbours Magazine, February 1944. p. 97.
- ↑ Neilson, Reid works list, compiled by Austrian locomotive historian Bernhard Schmeiser
- ↑ The South African Railways - Historical Survey. Editor George Hart, Publisher Bill Hart, Sponsored by Dorbyl Ltd., Published c. 1978, p. 25.
- 1 2 3 South African Railways and Harbours Locomotive Diagram Book, 2'0" & 3'6" Gauge Steam Locomotives, 15 August 1941, as amended
- ↑ Holland, D.F. (1972). Steam Locomotives of the South African Railways, Volume 2: 1910-1955 (1st ed.). Newton Abbott, Devon: David & Charles. p. 140. ISBN 978-0-7153-5427-8.
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