South African Class 7A 4-8-0

This article is about one of several different Cape Government Railways locomotive types to be designated "7th Class". For the others, see Cape Government Railways 7th Class locomotives.
CGR 7th Class 4-8-0 1896
Sudan Railways Dongola Class
South African Class 7A & 7AS 4-8-0

Ex CGR (Eastern System) 7th Class no. 726
SAR Class 7A no. 1009 with modified Type ZC tender
Type and origin
♠ - Original locomotive, as built
♥ - Locomotive equipped with superheating
Power type Steam
Designer Cape Government Railways
(H.M. Beatty)
Builder Sharp, Stewart and Company
Dübs and Company
Neilson and Company
Serial number Sharp, Stewart 4145-4152, 4363
Dübs 3355-3362, 3641-3652, 3976
Neilson 4920-4931, 5160-5163, 5232-5234, 5280-5281, 5345-5347
Model CGR 7th Class
Build date 1896-1898, 1901
Total produced 46
Specifications
Configuration 4-8-0 (Mastodon)
Driver 2nd coupled axle
Gauge 3 ft 6 in (1,067 mm) Cape gauge
Leading dia. 28 1⁄2 in (724 mm)
Coupled dia. 42 3⁄4 in (1,086 mm)
Tender wheels 33 1⁄2 in (851 mm) as built
34 in (864 mm) retyred
Wheelbase 46 ft 2 in (14,072 mm)
 • Engine 21 ft 3 1⁄2 in (6,490 mm)
 • Leading 5 ft 3 in (1,600 mm)
 • Coupled 12 ft (3,658 mm)
 • Tender 16 ft 1 in (4,902 mm)
 • Tender bogie 4 ft 7 in (1,397 mm)
Length:
 ​
 • Over couplers 53 ft 5 1⁄4 in (16,288 mm)
Height 12 ft 10 in (3,912 mm)
Frame type Plate
Axle load ♠ 9 LT (9,144 kg)
♥ 9 LT 14 cwt (9,856 kg)
 • Leading ♠ 10 LT 14 cwt (10,870 kg)
♥ 11 LT 2 cwt (11,280 kg)
 • 1st coupled ♠ 9 LT (9,144 kg)
♥ 9 LT 8 cwt (9,551 kg)
 • 2nd coupled ♠ 9 LT (9,144 kg)
♥ 9 LT 14 cwt (9,856 kg)
 • 3rd coupled ♠ 8 LT 18 cwt (9,043 kg)
♥ 9 LT 10 cwt (9,652 kg)
 • 4th coupled ♠ 8 LT 18 cwt (9,043 kg)
♥ 9 LT 8 cwt (9,551 kg)
 • Tender axle 8 LT 10 cwt 2 qtr (8,662 kg) av.
Adhesive weight ♠ 35 LT 16 cwt (36,370 kg)
♥ 37 LT 16 cwt (38,410 kg)
Loco weight ♠ 46 LT 10 cwt (47,250 kg)
♥ 49 LT 2 cwt (49,890 kg)
Tender weight 34 LT 2 cwt (34,650 kg)
Total weight ♠ 80 LT 12 cwt (81,890 kg)
♥ 83 LT 4 cwt (84,540 kg)
Tender type ZC (2-axle bogies)
ZA, ZB, ZC, ZE permitted
Fuel type Coal
Fuel capacity 5 LT 10 cwt (5.6 t)
Water cap 2,600 imp gal (11,800 l)
Firebox type Round-top
 • Firegrate area ♠ 17.5 sq ft (1.63 m2)
♥ 18 sq ft (1.7 m2)
Boiler:
 ​
 • Pitch ♠ 6 ft 8 in (2,032 mm) pitch
♥ 6 ft 10 in (2,083 mm)
 • Diameter ♠ 4 ft 4 in (1,321 mm)
♥ 4 ft 6 in (1,372 mm)
 • Tube plates ♠♥ 10 ft 9 in (3,277 mm)
 • Small tubes ♠ 185: 1 7⁄8 in (48 mm)
♥ 100: 1 7⁄8 in (48 mm)
 • Large tubes ♥ 18: 5 1⁄2 in (140 mm)
Boiler pressure ♠ 160 psi (1,103 kPa)
170 psi (1,172 kPa) adjusted
♥ 180 psi (1,241 kPa)
Safety valve Ramsbottom
Heating surface ♠ 1,078 sq ft (100.1 m2)
♥ 919 sq ft (85.4 m2)
 • Tubes ♠ 976 sq ft (90.7 m2)
♥ 806 sq ft (74.9 m2)
 • Firebox ♠ 102 sq ft (9.5 m2)
♥ 113 sq ft (10.5 m2)
Superheater:
 ​
 • Heating area ♥ 206 sq ft (19.1 m2)
Cylinders Two
Cylinder size 17 in (432 mm) bore
23 in (584 mm) stroke
Valve gear Stephenson
Valve type ♠ Slide - ♥ Piston
Couplers Johnston link-and-pin
AAR knuckle (1930s)
Performance figures
Tractive effort ♠ 18,660 lbf (83.0 kN) @ 75%
♠ 19,810 lbf (88.1 kN) @ 75% adjusted
♥ 22,240 lbf (98.9 kN) @ 75%
Factor of adh. 4.3
Career
Operators Cape Government Railways
Bechuanaland Railway
Imperial Military Railways
Imvani-Indwe Railway
Sudan Military Railway
South African Railways
Zambesi Saw Mills
Class CGR 7th Class, SAR Class 7A
Number in class 46 CGR, 44 SAR
Numbers CGR 347-350, 385-398, 718-744, 758
BR 4-7
IMR C522, C523 & C525-C527
Imvani-Indwe: Named
SAR 988-1031
Sudan 26-33
Delivered 1896-1901
First run 1896
Withdrawn 1972
The leading coupled axle had flangeless wheels

The South African Railways Class 7A 4-8-0 of 1896 was a steam locomotive from the pre-Union era in the Cape of Good Hope.

Between 1896 and 1901, the Cape Government Railways placed a second batch of altogether 46 7th Class steam locomotives with a 4-8-0 Mastodon wheel arrangement in service on its Midland and Eastern Systems. In 1912, when all but two of them were assimilated into the South African Railways, they were renumbered and designated Class 7A.[1][2][3]

In 1897 and 1898, during Kitchener's military campaign in Sudan, eight Cape 7th Class locomotives were built to the same design for the Soudan Military Railway.[4][5]

Manufacturers

The original Cape 7th Class locomotive had been designed in 1892 by H.M. Beatty, at the time the Cape Government Railways (Western System) Locomotive Superintendent.[6]

H.M. Beatty

Following on the 38 7th Class locomotives which were placed in service by the Cape Government Railways (CGR) between 1892 and 1893, a second batch of 46 slightly improved locomotives were acquired between 1896 and 1901. Outwardly, all these locomotives appeared almost identical to the first batch of 7th Class locomotives, but they had increased heating capacity as well as some other modifications. They were the first to be equipped with type ZC tenders, which rode on two two-axle bogies and had a capacity of 5 long tons 10 hundredweight (5.6 tonnes) of coal and 2,600 imperial gallons (11,800 litres) of water.[1][7][8]

1896

In 1896, orders were placed for 28 locomotives, distributed between three manufacturers.[1][5]

1897

In 1897, a further four 7th Class locomotives were ordered by the CGR from Neilson, for use on the new Vryburg to Bulawayo line of the fledgling Bechuanaland Railway Company (BR). The line was still under construction and was operated by the CGR on behalf of the BR at the time. These 7th Class locomotives, numbered in the range from BR4 to BR7, were eventually returned to the CGR and renumbered in the range from 347 to 350 for the Midland System.[1][5]

In 1897 and 1898, Neilson also built eight Cape 7th Class locomotives for the Soudan Military Railway, where they were known as the Dongola Class.[4][5]

1898

In 1898, another ten 7th Class locomotives were taken into service by the CGR, as well as another three by the Imvani-Indwe Railway which operated a branch line from Sterkstroom to the Indwe Collieries in the Eastern Cape.[1]

1901

One more 7th Class locomotive was delivered by Dübs in 1901 and became the Eastern System's no. 758.[5]

Class 7 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 were only implemented with effect from 1 January 1912.[2][9]

When all but two of these 46 locomotives were assimilated into the South African Railways (SAR) in 1912, they were renumbered in the range from 988 to 1031 and designated Class 7A. The two exceptions had been sold to Pauling and Company in 1909.[1][2][10]

The rest of the CGR's 7th Class locomotives, together with 7th Class locomotives from the Central South African Railways (CSAR), the Pretoria-Pietersburg Railway (PPR), the Rhodesia Railways (RR), the Natal Government Railways (NGR) and, in 1925, the New Cape Central Railways (NCCR), were grouped into six different sub-classes by the SAR and designated Classes 7 and 7B to 7F.[7][8]

Modification

During the 1930s and later, many of the Class 7 series locomotives were equipped with superheated boilers and piston valves. On the Class 7B and Class 7C, this conversion was sometimes indicated with an "S" suffix to the class number on the locomotive's number plates, but on the rest of the Class 7 family this distinction was rarely applied. The superheated versions could be visually identified by the position of the chimney on the smokebox, the chimney having been displaced forward to provide space behind it in the smokebox for the superheater header.[3][7][8]

In the early 1960s, Class 7A no. 1021 was reportedly equipped with a superheater and reclassified to the sole Class 7AS. The number plate was altered by weld-writing a crude "S" after the "7A". This locomotive spent its last working days on the SAR doing steam heating tests on mainline passenger coaches at the Braamfontein North passenger yard in Johannesburg, before being sold to the Zambesi Saw Mills (ZSM) in 1971. The ZSM engineer's records, however, show it as not superheated and having saturated boiler no. 7865.

Renumbering

During their long service lives, some of the Class 7A locomotives underwent more than one renumbering. Five saw service with the Imperial Military Railways (IMR) during the Second Boer War and were temporarily renumbered accordingly, three were unnumbered, but named, while in Imvani-Indwe colliery service and all but two were eventually renumbered onto the SAR roster in 1912. Table 1 lists these renumberings as well as their builders and works numbers.[1][2][10]

When the four BR locomotives, numbers BR 4 to BR 7, were eventually returned to CGR service and renumbered in the range from 347 to 350 for the Midland System, it resulted in number duplication which confused historians in later years. These four engine numbers had been used previously on four of the 1892 and 1893 batch of 7th Class locomotives, also built by Neilson, which had since been renumbered in the range from 712 to 715 when they were transferred from the Midland to the Eastern System.[1][2][5]

Service

South Africa

The 7th Class series became the main goods locomotive class for the last twenty years of the existence of the CGR. In SAR service, the Class 7 series worked on every system in the country. Of this second batch of the Class, not all began their service lives on the CGR, and not all remained with the CGR until the SAR came into existence. In summary:

South West Africa

In 1915, shortly after the outbreak of the First World War, the German South West Africa colony was occupied by the Union Defence Forces. Since a large part of the territory's railway infrastructure and rolling stock was destroyed or damaged by retreating German forces, an urgent need arose for locomotives for use on the Cape gauge lines in that territory. In 1917, numbers 1000 to 1002, 1005, 1006, 1017, 1019 and 1021 to 1024 were transferred to the Defence Department for service in South West Africa.[3][5][11]

These eleven locomotives remained in South West Africa after the war. They proved to be so successful in that territory, that more were gradually transferred there in later years. By the time the Class 24 locomotives arrived in SWA in 1949, 53 locomotives of the Class 7 family were still in use there.[3][5]

Most remained there, and were only transferred back to South Africa when the Class 32-000 diesel-electric locomotives replaced them in 1961. In South Africa, they remained in branchline service until they were finally withdrawn in 1972.[3]

Industrial

Four Class 7A locomotives, numbers 992 and 1006 in 1966, and 993 and 1021 in 1971, as well as two Class 7 and two Class 7B locomotives were sold to the Zambesi Saw Mills (ZSM) in Zambia. The company worked the teak forests which stretched 100 miles (160 kilometres) to the north-west of Livingstone, where it built one of the longest logging railways in the world to serve its sawmill at Mulobezi. These eight locomotives joined eight ex RR 7th Class locomotives which had been acquired by the ZSM between 1925 and 1956.[5]

Railway operations ceased at Mulobezi around 1972 and operation of the line to Livingstone was taken over by the Zambia Railways in 1973. While most of the Class 7 series locomotives remained at Mulobezi out of use, Class 7A no. 1021 was installed at the Livingstone factory to supply steam for curing wood.[12]

Sudan's Dongola Class

Sudan Dongola Class 4-8-0, c. 1898

Cape 7th Class locomotives were also built for the Soudan Military Railway during Kitchener's campaign in Sudan. When he arrived in the territory in 1895, he built a railway line, strictly for military purposes, running parallel to the Nile River for nearly 200 miles (322 kilometres) from Wadi Halfa to the Third Cataract at Kerma, and then another line from Wadi Halfa across 571 miles (919 kilometres) through the Nubian Desert to Atbarah and on to Khartoum to the south. For motive power, three Cape 7th Class locomotives, built to the Class 7A design and known as the Dongola Class in Sudan, were ordered from Neilson and delivered in 1897. These were followed by five more in two batches in 1898. They were initially not numbered, but named after places in Sudan.[4][5]

Their works numbers, order numbers, names and eventual Sudan Railway (SR) numbers, are listed in Table 2. SR no. 29, which was originally named Berber according to Neilson's records, was later renamed Fashoda/Suakin.[4][5]

These locomotives were equipped with gates across the open ends of their cabs and pipes under the running board on the right side, which terminated in hose connections below the front buffer beam, so that water tenders could be coupled to the front and they could be run cab forward. The reason was that they were used on a single line which was still being constructed into the desert from Wadi Halfa and which initially had no water supply at the far end.[5]

For some reason, these locomotives were not popular in the Sudan and they were all withdrawn from service by 1914.[5]

Illustration

References

Wikimedia Commons has media related to South African Class 7A 4-8-0.
  1. 1 2 3 4 5 6 7 8 9 10 Holland, D.F. (1971). Steam Locomotives of the South African Railways, Volume 1: 1859-1910 (1st ed.). Newton Abbott, Devon: David & Charles. pp. 41–44, 83. ISBN 978-0-7153-5382-0.
  2. 1 2 3 4 5 Classification of S.A.R. Engines with Renumbering Lists, issued by the Chief Mechanical Engineer's Office, Pretoria, January 1912, pp. 8, 12, 15, 38-39 (Reprinted in April 1987 by SATS Museum, R.3125-6/9/11-1000)
  3. 1 2 3 4 5 6 Paxton, Leith; Bourne, David (1985). Locomotives of the South African Railways (1st ed.). Cape Town: Struik. pp. 46–48. ISBN 0869772112.
  4. 1 2 3 4 5 Neilson, Reid works list, compiled by Austrian locomotive historian Bernhard Schmeiser
  5. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Pattison, R.G. (1997). The Cape Seventh Class Locomotives (1st ed.). Kenilworth, Cape Town: The Railway History Group. pp. 7–10, 22–24, 38–39, 48–50. ISBN 0958400946.
  6. ↑ 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, January 1944. pp. 9-10.
  7. 1 2 3 South African Railways & Harbours/Suid Afrikaanse Spoorweë en Hawens (15 Aug 1941). Locomotive Diagram Book/Lokomotiefdiagramboek, 3'6" Gauge/Spoorwydte. SAR/SAS Mechanical Department/Werktuigkundige Dept. Drawing Office/Tekenkantoor, Pretoria. p. 41.
  8. 1 2 3 South African Railways & Harbours/Suid Afrikaanse Spoorweë en Hawens (15 Aug 1941). Locomotive Diagram Book/Lokomotiefdiagramboek, 2'0" & 3'6" Gauge/Spoorwydte, Steam Locomotives/Stoomlokomotiewe. SAR/SAS Mechanical Department/Werktuigkundige Dept. Drawing Office/Tekenkantoor, Pretoria. pp. 6a-7a, 41-42.
  9. ↑ The South African Railways - Historical Survey. Editor George Hart, Publisher Bill Hart, Sponsored by Dorbyl Ltd., Published c. 1978, p. 25.
  10. 1 2 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 978-0-7153-5427-8.
  11. ↑ Espitalier, T.J.; Day, W.A.J. (1947). The Locomotive in South Africa - A Brief History of Railway Development. Chapter VII - South African Railways (Continued). South African Railways and Harbours Magazine, December 1947. p. 1033.
  12. ↑ Pattison, R.G. (2005). Thundering Smoke, (1st ed.). Sable Publishing House. p42-48. ISBN 0-9549488-1-5
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