South African Class 16A 4-6-2
| South African Class 16A 4-6-2 | |
|---|---|
|
No. 852, Braamfontein, Johannesburg, June 1936 | |
| Type and origin | |
| Power type | Steam |
| Designer | South African Railways |
| Builder | North British Locomotive Company |
| Serial number | 20956-20957 [1][2] |
| Model | Class 16A |
| Build date | 1915 |
| Total produced | 2 |
| Specifications | |
| Configuration | 4-6-2 "Pacific" |
| Gauge | 3 ft 6 in (1,067 mm) Cape gauge |
| Leading wheel diameter | 30 in (762 mm) |
| Driver diameter | 60 in (1,520 mm) |
| Trailing wheel diameter | 33 in (838 mm) |
| Wheelbase |
Total: 57 ft 7.25 in (17.558 m) Engine: 6 ft 2 in (1.880 m) bogie 10 ft 9 in (3.277 m) coupled 31 ft 1 in (9.474 m) total Tender: 4 ft 7 in (1.397 m) bogie 16 ft 9 in (5.105 m) total |
| Length | 65 ft 11.625 in (20.107 m) total |
| Height | 12 ft 10 in (3.912 m) |
| Axle load | 16.9 long tons (17.2 t) per driver |
| Weight on drivers | 40.7 long tons (41.4 t) |
| Locomotive weight | 81.1 long tons (82.4 t) |
| Tender weight |
49,452 lb (22.4 t) empty 51.05 long tons (51.9 t) w/o |
| Locomotive and tender combined weight | 132.25 long tons (134.4 t) |
| Tender type |
MP1 - MP, MP1, MR, MS, MT, MT1, MT2, MX, MY, MY1 permitted * 2 axle bogies * 34 in (864 mm) wheels * Length 25 ft 10.75 in (7.893 m) |
| Fuel type | Coal |
| Fuel capacity | 10 long tons (10.2 t) |
| Water capacity | 4,250 imp gal (19,300 l) |
| Boiler |
5 ft 1.625 in (1.565 m) inside diameter 19 ft 9 in (6.020 m) inside length 7 ft 9 in (2.362 m) pitch |
| Boiler pressure | 200 psi (1,380 kPa) |
| Firegrate area | 36 sq ft (3.345 m2) |
| Heating surface: – Tubes |
119 tubes 2.25 in (57.1 mm) diameter 21 tubes 5.5 in (140 mm) diameter 1,975.5 sq ft (183.530 m2) |
| – Firebox | 146 sq ft (13.564 m2) |
| – Total | 2,121.5 sq ft (197.094 m2) |
| Superheater area | 459.5 sq ft (42.689 m2) |
| Cylinders | Four |
| Cylinder size |
14 in (356 mm) bore 26 in (660 mm) stroke [1] |
| Valve gear | Walschaerts |
| Performance figures | |
| Tractive effort | 25,480 lbf (113 kN) at 75% pressure |
| Career | |
| Operator(s) | South African Railways [1] |
| Class | Class 16A |
| Number in class | 2 |
| Number(s) | 851-852 |
| Delivered | 1915 |
| First run | 1915 |
| Withdrawn | 1945 |
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The South African Class 16A 4-6-2 of 1915 is a South African steam locomotive from the South African Railways era.
In 1915 the South African Railways placed two Class 16A four-cylinder simple expansion steam locomotives with a 4-6-2 Pacific type wheel arrangement in passenger train service.[3]
Manufacturer
The Class 16A 4-6-2 Pacific type locomotive was designed by D.A. Hendrie, Chief Mechanical Engineer (CME) of the South African Railways (SAR) from 1910 to 1922, and was built in 1915 by the North British Locomotive Company (NBL) in Glasgow, Scotland. Two locomotives were delivered, numbered 851 and 852. Also superheated and with Walschaerts valve gear and Belpaire fireboxes, they were identical in most respects to their predecessor, the Class 16 that was delivered by NBL a year earlier, except that they had four cylinders instead of the usual two.[3]
Four-cylinder experiment
With the Class 16A the SAR experimented with four-cylinder simplex steam power. All four cylinders were arranged in line below the smokebox. The locomotive used Walschaerts valve gear with rocker arms attached to the tail ends of the outer piston valves, which then operated the adjacent inner piston’s valves. It operated in the simple expansion configuration whereby steam is fed directly to all four cylinders and used steam is exhausted by all cylinders directly through the smokebox and up the chimney.[3]
All four cylinders were the same size with a 14 inches (356 millimetres) bore and 26 inches (660 millimetres) stroke, which presented a number of problems that had to be overcome to arrange two of these in the limited space between the frames. The outer cylinders drove the centre driving wheels while the inner cylinders operated on a cranked leading driving wheel axle, with each inside crank arranged at an angle of 180 degrees with its adjacent outside crank.[1]
The arrangement made for a very smooth running locomotive capable of very fast running, since the shouldering effect that occurs on two-cylinder locomotives was completely absent. They were very popular with their crews because of their smooth and steady running.[1]
They did, however, have less tractive effort than the two-cylinder Class 16. Even though the Class 16A experiment was successful, the available space on a Cape gauge locomotive prevented larger cylinders from being fitted, and the four-cylinder design was therefore never repeated by the SAR.[4]
Service
The two locomotives were placed in service on the Reef, where they operated with reasonable success. Their biggest disadvantage was the difficult access to the inner cylinders. They were withdrawn by 1945.[3]
Sides illustrated
The main picture shows number 852 on train Number 75, departing Braamfontein in June 1936, while a side view is shown in the builder's picture below.
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Number 852 in the 1922 SAR battleship gray livery
See also
- List of South African locomotive classes
- South African Class 16 4-6-2
- South African Class 16B 4-6-2
- South African Class 16C 4-6-2
- South African Class 16D 4-6-2
- South African Class 16DA 4-6-2
- South African Class 16E 4-6-2
- South African locomotive history
- Tender locomotive numbering and classification
- The 4-6-2 "Pacific"
References
|
- ↑ 1.0 1.1 1.2 1.3 1.4 Holland, D.F. (1972). Steam Locomotives of the South African Railways, Volume 2: 1910-1955 (1st ed.). Newton Abbott, Devon: David & Charles. p. 30. ISBN 978-0-7153-5427-8.
- ↑ North British Locomotive Company works list, compiled by Austrian locomotive historian Bernhard Schmeiser
- ↑ 3.0 3.1 3.2 3.3 Paxton, Leith; Bourne, David (1985). Locomotives of the South African Railways (1st ed.). Cape Town: Struik. pp. 10–11, 65–66. ISBN 0869772112.
- ↑ Durrant, A E (1989). Twilight of South African Steam (1st ed.). Newton Abbott, London: David & Charles. pp. 17–18. ISBN 0715386387.
