| South African Class 15B 4-8-2 & South African Class 15BR 4-8-2 |
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| Class 15BR, REGM R7 (ex SAR 1990) on the Randfontein Estates Gold Mine’s Doornkop branch, 14 September 1997 | |
| Power type | Steam |
| Designer | South African Railways |
| Builder | Montreal Locomotive Works |
| Serial number | 58440-58449, 61424-61443[1] |
| Model | Class 15B |
| Build date | 1918-1922 |
| Total produced | 30 |
| Configuration | 4-8-2 "Mountain" |
| Gauge | 3 ft 6 in (1,067 mm) Cape gauge |
| Leading wheel diameter |
28.5 in (724 mm) |
| Driver diameter | 57 in (1,450 mm) |
| Trailing wheel diameter |
33 in (838 mm) |
| Wheelbase | Total: 62 ft 7.25 in (19.082 m) Engine: 6 ft 2 in (1.880 m) pilot 15 ft (4.572 m) coupled 33 ft 9 in (10.287 m) total Tender: 4 ft 7 in (1.397 m) bogie 17 ft 11 in (5.461 m) total |
| Length | 70 ft 5.125 in (21.466 m) |
| Height | 12 ft 10 in (3.912 m) as built 13 ft 0.75 in (3.981 m) reboilered |
| Frame | Bar frame |
| Axle load | 16.55 long tons (16.8 t) on 4th driver as built 16.55 long tons (16.8 t) on 1st driver reboilered |
| Weight on drivers | 65.1 long tons (66.1 t) as built 65.15 long tons (66.2 t) reboilered |
| Locomotive weight | 91.7 long tons (93.2 t) as built 91.75 long tons (93.2 t) reboilered |
| Tender weight | 49,116 lb (22.3 t) empty 50.9 long tons (51.7 t) w/o |
| Locomotive & tender combined weight |
172,900 lb (78.4 t) empty 142.6 long tons (144.9 t) w/o |
| Tender type | LP * 2 axle bogies * Wheels 34 in (864 mm) dia * Length 27 ft .25 in (8.236 m) |
| Fuel type | Coal |
| Fuel capacity | 10 long tons (10.2 t) |
| Water capacity | 4,250 imp gal (19,300 l) |
| Boiler | As built: 5 ft 4.1875 in (1.630 m) int dia 18 ft (5.486 m) int length 7 ft 9 in (2.362 m) pitch Reboilered: 5 ft 7.5 in (1.715 m) int dia 21 ft 8 in (6.604 m) int length, steel firebox 21 ft 7.625 in (6.594 m) int length, copper firebox 8 ft 1.5 in (2.477 m) pitch |
| Boiler pressure | 185 psi (1,280 kPa) as built & reboilered 190 psi (1,310 kPa) cylinders bushed |
| Firegrate area | 40 sq ft (3.716 m2) as built 37 sq ft (3.437 m2) reboilered |
| Heating surface: Tubes |
As built: 113 tubes 2.25 in (57.2 mm) ext dia 21 tubes 5.5 in (140 mm) ext dia 1,840 sq ft (170.942 m2) Reboilered: 87 tubes 2.5 in (63.5 mm) ext dia 30 tubes 5.5 in (140 mm) ext dia 2,171 sq ft (201.692 m2) |
| Heating surface: Firebox |
188 sq ft (17.466 m2) as built 143 sq ft (13.285 m2) reboilered |
| Heating surface: Total |
2,028 sq ft (188.407 m2) as built 2,313 sq ft (214.885 m2) reboilered |
| Superheater area | 446 sq ft (41.435 m2) as built 537 sq ft (49.889 m2) reboilered |
| Cylinders | Two |
| Cylinder size | 22 in (559 mm) bore as built 21.75 in (552 mm) bore bushed 28 in (711 mm) stroke |
| Valve gear | Walschaerts |
| Tractive effort | At 75% boiler pressure: 32,990 lbf (146.7 kN) as built and reboilered 33,130 lbf (147.4 kN) bushed[2] |
| Career | South African Railways Caminhos de Ferro de Moçambique Tweefontein United Collieries Randfontein Estates Gold Mine |
| Class | Class 15B, Class 15BR |
| Number in class | 30 |
| Number | 1829–1838, 1971-1990 |
| Delivered | 1918-1922 |
| First run | 1918 |
| Withdrawn | 1976 |
| Disposition | Retired |
Between 1918 and 1922 the South African Railways placed ten Class 15B steam locomotives with a 4-8-2 Mountain wheel arrangement in service.[3]
Contents |
As a result of wartime disruption in Europe, the first batch of ten Class 15B 4-8-2 steam locomotives for the South African Railways (SAR) was ordered from the Montreal Locomotive Works (MLW) in Canada. They were built and delivered in 1918, numbered 1829 to 1838. A second batch of twenty locomotives was ordered from the same builders and delivered in 1922, numbered 1971 to 1990. They were built to the general specifications of the Class 15, but with bar frames and some typical North American features, and they were equipped with Belpaire fireboxes with combustion chambers.[1][3]
As they went in for major overhauls, these locomotives had their cylinders bushed to reduce the bore from the as built 22 to 21.75 inches (559 to 552 millimetres). At the same time their operating boiler pressure was adjusted upwards from 185 to 190 pounds per square inch (1,280 to 1,310 kilopascals).[2]
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.[2][3]
Eventually all thirty Class 15B locomotives were reboilered with Watson Standard no. 2A boilers and reclassified to Class 15BR. Early conversions were equipped with copper and later conversions with steel fireboxes. In the process they were also equipped with Watson cabs, with their distinctive slanted fronts compared to the conventional vertical fronts of their original cabs.[2]
An obvious visual 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 Class 15B and Class 15BR two even more obvious visual differences are the Watson cab and the absence of the Belpaire firebox hump between the cab and boiler on the reboilered locomotives.[2][3]
The Class 15B was placed in service in the eastern Orange Free State, but eventually spent most of their working lives in the Cape Midlands, working south from Noupoort to Cradock and across to De Aar. When the Class 15F started taking over in that area, they were gradually relocated to Cape Town from where they worked goods and passenger trains to the north. They were also used across Sir Lowry's Pass to Caledon in the Overberg and on the Bitterfontein line via Malmesbury and Klawer.[1][3]
Some were shedded at Worcester and at Ashton for shunting. The usual way of exchanging the Ashton shunter every fortnight was for it to be used on the local passenger train, which was normally hauled by a Garratt. They were withdrawn by 1976.[4]
In March and July 1973 twelve Class 15BR locomotives were sold in two batches to Caminhos de Ferro de Moçambique (CFM), the Mozambique Railways, where they were mainly used for shunting at Lourenco Marques and occasionally on freight service to Swaziland. The SAR running numbers of these locomotives were 1836, 1974, 1981, 1983, 1984 and 1986, sold in March 1973, and 1829, 1831, 1838, 1976, 1977 and 1985, sold in July 1973. The CFM renumbered the March batch 421, 426 and 422 to 425, and the July batch 427 to 432, but this renumbering sequence could not be ascertained with certainty.[4]
Six Class 15BR locomotives were sold into industrial use.
The main picture shows REGM number R7, ex SAR Class 15BR 1990, heading a mine manager's tour of the REGM system, seen here on the Doornkop branch on 14 September 1997.
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