South African Class 7D 4-8-0

Rhodesia Railways 7th Class
South African Class 7D 4-8-0

RR 7th Class no. MR11, then no. MR18, then no. RRM67, then SAR Class 7D no. 1353
Type and origin
♠ Original locomotive, as built
♥ Locomotive equipped with superheating
Power type Steam
Designer Cape Government Railways
(H.M. Beatty)
Builder Neilson, Reid and Company
Kitson and Company
North British Locomotive Company
Order number NR E834 & E835 (1899), E851 (1900)
NBL L313 & L322 (1903)
Serial number NR 5675-5686, 5791-5802, 5817
Kitson 4062-4069
NBL 16085-16094, 16171-16180
Model CGR 7th Class
Build date 1899-1903
Total produced 52
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)
♥ 38 LT (38,610 kg)
Loco weight ♠ 46 LT 10 cwt (47,250 kg)
44 LT 7 cwt (45,060 kg) Kitson
♥ 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)
78 LT 9 cwt (79,710 kg) Kitson
♥ 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 or Belpaire
 • Firegrate area ♠ 17.5 sq ft (1.63 m2)
♥ 18 sq ft (1.7 m2)
Boiler:
 ​
 • Pitch ♠ 6 ft 8 in (2,032 mm)
♥ 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)
♥ 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 (1,240 kPa)
Safety valve Ramsbottom
Heating surface ♠ 1,078 sq ft (100.1 m2)
1,088 sq ft (101.1 m2) Kitson
♥ 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)
112 sq ft (10.4 m2) Kitson
♥ 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. NR & NBL-built: 4.32
Kitson-built: 4.531
Career
Operators Imperial Military Railways
Mashonaland Railways
Rhodesia Railways Northern Ext
Rhodesia Railways
South African Railways
Class IMR, MR, RRM & RR 7th Class
SAR Class 7D
Number in class RR 52, SAR 5
Numbers BR 7-8, RR 1-50, IMR 110
SAR 1351-1355
Delivered 1899-1903 to RR, 1915 to SAR
First run 1899
Withdrawn 1972
The leading coupled axle had flangeless wheels

The South African Railways Class 7D 4-8-0 of 1915 was a steam locomotive.

Between 1899 and 1903, the Rhodesia Railways placed 52 Cape 7th Class 4-8-0 Mastodon steam locomotives in service. During the Second Boer War, one more was obtained from the Imperial Military Railways in March 1901, as replacement for a locomotive which was damaged beyond local repair capabilities as a result of hostilities during delivery.[1]

In May 1915, five of these locomotives were sold to the South African Railways, where they were renumbered and reclassified, four of them to Class 7D and the remaining one erroneously to Class 7B. At the same time, the ex Imperial Military Railways locomotive was also sold back to South Africa and was, also erroneously, designated Class 7D.[1][2][3]

Rhodesian 7th Class

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.[4]

H.M. Beatty

Between 1899 and 1903, 52 such Cape 7th Class 4-8-0 steam locomotives were built for the Beira and Mashonaland and Rhodesia Railways (BMR), later the Rhodesia Railways (RR). These locomotives were acquired by Southern Rhodesia at the time when railways were still expanding from South Africa via the Bechuanaland Protectorate into Southern Rhodesia in the southwest, and from Beira in Mozambique to Umtali in the east, and while the Second Boer War was in progress. At the time, the system was composed of several smaller railways, still largely under construction, which were eventually all linked up in 1902. These were:[1]

Manufacturers

The 52 locomotives were ordered in five batches from three British manufacturers.[1][5][6]

In 1901, eleven of them were renumbered in the range from MR8 to MR18, MR20 and MR21, not in order, for the BMR. The exception was no. RR8, which was delivered damaged beyond local repair abilities, apparently as a result of hostilities, while in transit through the area under control of the British Military near Mafeking. A Neilson, Reid-built 7th Class locomotive of the Imperial Military Railways (IMR), no. IMR 110, was subsequently transferred to the BMR at Umtali in March 1901 as replacement for the damaged no. RR8. It was renumbered to MR19, the number which would have been allocated to no. RR8. The renumberings are tabled below.[1]

South African Railways

In May 1915, six of the Neilson, Reid-built 7th Class locomotives were purchased by the South African Railways (SAR) to augment its locomotive stock, which was being taxed severely due to war conditions at the time. These six locomotives included the war-damaged no. RR8 which had still not been repaired and consequently never ran a mile in revenue service in Rhodesia, as well as the ex IMR locomotive which had been transferred to Rhodesia as compensation for the damaged no. RR8.[1][2][3]

These locomotives were initially referred to as Class RR, until they were later designated SAR Class 7D. Five of them were renumbered in the range from 1351 to 1355 on the SAR roster. The sixth, SAR no. 949, was erroneously designated Class 7B.[1][2][3][7]

Classification errors

During this SAR classification and renumbering process, two of these locomotives were incorrectly classified, possibly as a result of their records getting exchanged in an apparent administrative error.[8]

Class 7 sub-classes

Other 7th Class locomotives which came onto the SAR roster from the other Colonial railways in the region in 1912, namely the CGR, CSAR, the Natal Government Railways (NGR) and, in 1925, from the New Cape Central Railways (NCCR), were grouped into six different sub-classes by the SAR, becoming SAR Classes 7, 7A to 7C, 7E and 7F.[9]

Modifications

During the 1930s, many of the Class 7 family of locomotives were equipped with superheating and piston valves. On the Class 7B and Class 7C, this conversion was sometimes indicated with an "S" suffix to the class letter on the locomotive number plates, but on the rest of the Class 7 family this distinction was not applied consistently. The superheated versions could be 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][9]

Service

South Africa

In SAR service, the Class 7 series worked on every system in the country. They remained in branch line service until they were finally withdrawn in 1972.[1][3]

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 1351 to 1353 were transferred to the Defence Department for service in South West Africa.[1][3][7]

These three locomotives remained in South West Africa after the war. The Class 7s 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. Most remained there and were only transferred back to South Africa when the Class 32-000 diesel-electric locomotives replaced them in 1961.[1][3]

Works numbers

Their builders, works numbers and renumbering are listed in the table.[1][2][5][6][10][11]

References

Wikimedia Commons has media related to South African Class 7D 4-8-0.
  1. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Pattison, R.G. (1997). The Cape Seventh Class Locomotives (1st ed.). Kenilworth, Cape Town: The Railway History Group. pp. 10–12, 25–33. ISBN 0958400946.
  2. 1 2 3 4 5 Holland, D.F. (1972). Steam Locomotives of the South African Railways, Volume 2: 1910-1955 (1st ed.). Newton Abbott, Devon: David & Charles. pp. 32–33. ISBN 978-0-7153-5427-8.
  3. 1 2 3 4 5 6 7 Paxton, Leith; Bourne, David (1985). Locomotives of the South African Railways (1st ed.). Cape Town: Struik. pp. 46–48. ISBN 0869772112.
  4. ↑ 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.
  5. 1 2 Neilson, Reid works list, compiled by Austrian locomotive historian Bernhard Schmeiser
  6. 1 2 North British Locomotive Company works list, compiled by Austrian locomotive historian Bernhard Schmeiser
  7. 1 2 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.
  8. 1 2 Holland, D.F. (1971). Steam Locomotives of the South African Railways, Volume 1: 1859-1910 (1st ed.). Newton Abbott, Devon: David & Charles. pp. 43, 123–124. ISBN 978-0-7153-5382-0.
  9. 1 2 South African Railways and Harbours Locomotive Diagram Book, 2'0" & 3'6" Gauge Steam Locomotives, 15 August 1941, as amended
  10. ↑ Pattison, R.G. (2005). Thundering Smoke, (1st ed.). Ilminster, Somerset: Sable Publishing House. pp. 42-48. ISBN 0-9549488-1-5.
  11. ↑ Durrant, A.E. (1997). The Smoke that Thunders, (1st ed.). Harare: African Publishing Group. ISBN 1-77901-134-2.
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