South African Class 15 4-8-2

The South African Railways Class 15 4-8-2 of 1914 was a steam locomotive.

South African Class 15 & 15AR 4-8-2
No. 1566, reboilered and reclassified to Class 15AR, Port Elizabeth, 3 April 1978
Type and origin ♠ Class 15 as built with a Belpaire firebox ♥ Class 15AR rebuilt with a Watson Standard boiler ♣ Steel firebox - ♦ Copper firebox Power type Steam Designer South African Railways (D.A. Hendrie) Builder North British Locomotive Company Serial number 20364-20373 Model Class 15 Build date 1914 Total produced 10
Specifications Configuration: ​  • Whyte 4-8-2 (Mountain)  • UIC 2'D1'h2 Driver 2nd coupled axle Gauge 3 ft 6 in (1,067 mm) Cape gauge Leading dia. 28 ^1⁄2 in (724 mm) Coupled dia. 57 in (1,448 mm) Trailing dia. 33 in (838 mm) Tender wheels 34 in (864 mm) Wheelbase 60 ft 6 in (18,440 mm)  • Engine 33 ft 8 in (10,262 mm)  • Leading 6 ft 2 in (1,880 mm)  • Coupled 15 ft (4,572 mm)  • Tender 16 ft 9 in (5,105 mm)  • Tender bogie 4 ft 7 in (1,397 mm) Length: ​  • Over couplers 68 ft 10 ^3⁄4 in (20,999 mm) Height ♠ 12 ft 10 in (3,912 mm) ♥ 12 ft 11 ^3⁄4 in (3,956 mm) Frame type Plate Axle load ♠♥♣ 16 LT 11 cwt (16,820 kg) ♥♦ 16 LT 14 cwt (16,970 kg)  • Leading ♠ 15 LT 14 cwt (15,950 kg) ♥♣ 16 LT 1 cwt (16,310 kg) ♥♦ 16 LT 6 cwt (16,560 kg)  • 1st coupled ♠♥♣ 16 LT 10 cwt (16,760 kg) ♥♦ 16 LT 13 cwt (16,920 kg)  • 2nd coupled ♠ 16 LT 10 cwt (16,760 kg) ♥♣ 16 LT 9 cwt (16,710 kg) ♥♦ 16 LT 6 cwt (16,560 kg)  • 3rd coupled ♠♥♣ 16 LT 11 cwt (16,820 kg) ♥♦ 16 LT 14 cwt (16,970 kg)  • 4th coupled ♠♥♣ 16 LT 9 cwt (16,710 kg) ♥♦ 16 LT 11 cwt (16,820 kg)  • Trailing ♠♥♣ 12 LT 6 cwt (12,500 kg) ♥♦ 12 LT 7 cwt (12,550 kg)  • Tender bogie Bogie 1: 27 LT 10 cwt (27,940 kg) Bogie 2: 23 LT 11 cwt (23,930 kg)  • Tender axle 13 LT 15 cwt (13,970 kg) Adhesive weight ♠ 66 LT (67,060 kg) ♥♣ 65 LT 19 cwt (67,010 kg) ♥♦ 66 LT 4 cwt (67,260 kg) Loco weight ♠ 94 LT (95,510 kg) ♥♣ 94 LT 6 cwt (95,810 kg) ♥♦ 94 LT 17 cwt (96,370 kg) Tender weight 51 LT 1 cwt (51,870 kg) Total weight ♠ 145 LT 1 cwt (147,400 kg) ♥♣ 145 LT 7 cwt (147,700 kg) ♥♦ 145 LT 18 cwt (148,200 kg) Tender type MP1 (2-axle bogies) MP, MP1, MR, MS, MT, MT1, MT2, MX, MY, MY1 permitted Fuel type Coal Fuel capacity 10 LT (10.2 t) Water cap 4,250 imp gal (19,300 l) Firebox type ♠ Belpaire - ♥ Round-top  • Firegrate area ♠ 40 sq ft (3.7 m^2) ♥ 37 sq ft (3.4 m^2) Boiler: ​  • Model Watson Standard no. 2A  • Pitch ♠ 7 ft 9 in (2,362 mm) ♥ 8 ft ^1⁄2 in (2,451 mm)  • Diameter ♠ 5 ft 4 ^5⁄8 in (1,641 mm) ♥ 5 ft 7 ^1⁄2 in (1,714 mm)  • Tube plates ♠ 21 ft 9 in (6,629 mm) ♥♣ 21 ft 8 in (6,604 mm) ♥♦ 21 ft 7 ^5⁄8 in (6,594 mm)  • Small tubes ♠ 131: 2 ^1⁄4 in (57 mm) ♥ 87: 2 ^1⁄2 in (64 mm)  • Large tubes ♠ 24: 5 ^1⁄2 in (140 mm) ♥ 30: 5 ^1⁄2 in (140 mm) Boiler pressure ♠ 185 psi (1,276 kPa) ♥ 190 psi (1,310 kPa) Safety valve ♠ Ramsbottom - ♥ Pop Heating surface ♠ 2,578 sq ft (239.5 m^2) ♥ 2,313 sq ft (214.9 m^2)  • Tubes ♠ 2,423 sq ft (225.1 m^2) ♥ 2,171 sq ft (201.7 m^2)  • Firebox ♠ 155 sq ft (14.4 m^2) ♥ 142 sq ft (13.2 m^2) Superheater: ​  • Heating area ♠ 601 sq ft (55.8 m^2) ♥ 537 sq ft (49.9 m^2) Cylinders Two Cylinder size 22 in (559 mm) bore 28 in (711 mm) stroke Valve gear Walschaerts Valve type Piston Couplers Johnston link-and-pin AAR knuckle (1930s)
Performance figures Tractive effort ♠ 32,990 lbf (146.7 kN) @ 75% ♥ 33,880 lbf (150.7 kN) @ 75%
Career Operators South African Railways Swaziland Railway Class Class 15 & 15AR Number in class 10 Numbers 1561-1570 Delivered 1914 First run 1914 Withdrawn 1980s
The leading coupled axle had flangeless wheels

In 1914, the South African Railways placed ten Class 15 steam locomotives with a 4-8-2 Mountain type wheel arrangement in service.[1][2][3]

Manufacturer

D.A. Hendrie, Chief Mechanical Engineer (CME) of the South African Railways (SAR), commenced with design work on the Class 15 in 1913. It was intended as a mixed-traffic locomotive for use in the Orange Free State, where gradients and curvature were less severe than on the coastal sections. The locomotive was similar in general layout to the Classes 12 and 14, but with larger 57 inches (1,448 millimetres) coupled wheels. Ten locomotives were built by the North British Locomotive Company (NBL) and delivered in February and March 1914, numbered in the range from 1561 to 1570.[1][2][4]

Characteristics

The engines had plate frames, Walschaerts valve gear, Belpaire fireboxes without combustion chambers and were superheated. They were delivered with Type MP1 tenders which had a coal capacity of 10 long tons (10.2 tonnes) and a water capacity of 4,250 imperial gallons (19,300 litres).[1][3][5][6]

D.A. Hendrie

To reduce the weight on the trailing wheels, steel fireboxes were originally used instead of copper since the water quality in the Free State was considered suitable for this metal. Some locomotives in Natal had been fitted with steel fireboxes years previously and the results were fairly good, but wherever water supplies were of poor quality, steel fireboxes gave a lot of trouble and necessitated the introduction of water treatment plants to prevent corrosion.[1][2][3][7]

This reintroduction of steel fireboxes eventually led to its widespread use on all the larger locomotive types, but it also forced the SAR to adopt locomotive water treatment as a general policy. There was no settled policy on water treatment for some years, but engines with copper fireboxes were used mainly in areas where the water was not of good quality. Hendrie followed a conservative policy in this respect and steel fireboxes were only to be fitted in large numbers by his successor, Colonel F.R. Collins DSO.[2]

In the case of the Class 15, it was still early days for water treatment and enough trouble was experienced to result in their steel fireboxes being replaced with copper fireboxes. The locomotive's one flaw was excessively long fire tubes. On later models like the Class 15A, Hendrie improved the boiler by adding a combustion chamber, which shortened the distance between tube plates from 21 feet 9 inches (6,629 millimetres) to 19 feet (5,791 millimetres).[1][2]

Watson Standard boilers

During the 1930s, many serving locomotives were reboilered with a standard boiler type designed by A.G. Watson, CME of the SAR from 1929 to 1936, as part of his standardisation policy. Such Watson Standard reboilered locomotives were reclassified by adding an "R" suffix to their classification.[3][5][6]

When all ten Class 15 locomotives were reboilered with Watson Standard no. 2A boilers, they were reclassified to Class 15AR since the only differences between the as-delivered Class 15 and the Class 15A lay in the length of their boilers and whether they were built with or without combustion chambers. In the process, the locomotives were also equipped with Watson cabs with their distinctive slanted fronts, compared to the conventional vertical fronts of their original cabs. During reboilering, some were equipped with steel and others with copper fireboxes.[2][3]

Their original Belpaire boilers were fitted with Ramsbottom safety valves, while the Watson Standard boiler was fitted with Pop safety valves. Another obvious 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 Classes 15 and 15AR, two even more obvious differences are the Watson cab and the absence of the Belpaire firebox hump between the cab and boiler on the reboilered locomotives.[5][6]

Service

The Class 15 was placed in service in the Orange Free State, shedded at Bloemfontein. After reboilering and reclassification, they became part of the much larger Class 15AR fleet and saw service widely throughout the country, getting used in every kind of role from dock shunting to mainline passenger work.[1][3]

The Cape Northern examples were scattered between De Aar, Kimberley and Klerksdorp. The Cape Midland was a major user of the Class, with locomotives shedded at Sydenham in Port Elizabeth, Klipplaat, Graaff Reinet and Noupoort. The Class 15AR also worked the suburban services between Port Elizabeth and Uitenhage until they were replaced by diesel power.[7]

Near the end of their service lives in the early 1980s, they were all relegated to shunting work at centres all around the country, except for some which were hired out to Swaziland and which were still employed in mainline service on the Swaziland Railway until they were also eventually replaced by diesel traction and retired.[7]

Illustration

The main picture, showing the reboilered and reclassified Class 15AR no. 1566 at Port Elizabeth, and the following illustrate the Class before and after modification.

• 
  Class 15AR No. 1568 with a modified Type MP1 tender, Midlandia, 1979
• 
  No. 1561 as built, with an as-delivered Type MP1 tender and Belpaire firebox, c. 1914

References

1. Holland, D. F. (1972). Steam Locomotives of the South African Railways. 2: 1910-1955 (1st ed.). Newton Abbott, Devon: David & Charles. p. 26. ISBN 978-0-7153-5427-8.
2. Espitalier, T.J.; Day, W.A.J. (1945). The Locomotive in South Africa - A Brief History of Railway Development. Chapter VII - South African Railways (Continued). South African Railways and Harbours Magazine, July 1945. p. 516.
3. Paxton, Leith; Bourne, David (1985). Locomotives of the South African Railways (1st ed.). Cape Town: Struik. pp. 10–11, 59–60. ISBN 0869772112.
4. North British Locomotive Company works list, compiled by Austrian locomotive historian Bernhard Schmeiser
5. 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. 43.
6. 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, 43.
7. Durrant, A. E. (1989). Twilight of South African Steam (1st ed.). Newton Abbott, London: David & Charles. pp. 83–84. ISBN 0715386387.