| South African Class HF 2-8-2+2-8-2 | |
|---|---|
| Class HF 1386, circa 1940 | |
| Power type | Steam |
| Designer | South African Railways |
| Builder | Henschel and Son |
| Serial number | 20698-20707, 21052[1][2] |
| Model | Class HF |
| Build date | 1926-1927 |
| Total produced | 11 |
| Configuration | 2-8-2+2-8-2 "Double Mikado" Modified Fairlie |
| Gauge | 3 ft 6 in (1,067 mm) Cape gauge |
| Leading wheel diameter |
28.5 in (724 mm) |
| Driver diameter | 46 in (1,170 mm) |
| Trailing wheel diameter |
28.5 in (724 mm) |
| Wheelbase | Total: 69 ft 10 in (21.285 m) Engines: 12 ft 9 in (3.886 m) coupled 22 ft 10.5 in (6.972 m) total |
| Length | 77 ft 6.75 in (23.641 m) |
| Height | 12 ft 11.75 in (3.956 m) |
| Frame | Bar frame, 42 ft 1 in (12.827 m) between pivot centres |
| Axle load | 13.1 long tons (13.3 t) on 7th & 8th drivers |
| Weight on drivers | 102.8 long tons (104.4 t) |
| Locomotive weight | 150.05 long tons (152.5 t) w/o |
| Fuel type | Coal |
| Fuel capacity | 9 long tons (9.1 t) |
| Water capacity | 3,000 imp gal (14,000 l) front 1,600 imp gal (7,300 l) rear |
| Boiler | 5 ft 11.125 in (1.807 m) int dia 15 ft (4.572 m) int length |
| Boiler pressure | 180 psi (1,240 kPa) |
| Firegrate area | 53 sq ft (4.924 m2) |
| Heating surface: Tubes |
169 tubes 2 in (50.8 mm) ext dia 34 tubes 5.5 in (140 mm) ext dia 2,062 sq ft (191.566 m2) |
| Heating surface: Flues |
25 sq ft (2.323 m2) |
| Heating surface: Firebox |
184 sq ft (17.094 m2) |
| Heating surface: Total |
2,271 sq ft (210.983 m2) |
| Superheater area | 598 sq ft (55.556 m2) |
| Cylinders | Four |
| Cylinder size | 18 in (457 mm) bore 24 in (610 mm) stroke |
| Valve gear | Walschaerts[3] |
| Tractive effort | 45,640 lbf (203.0 kN) at 75% boiler pressure |
| Career | South African Railways |
| Class | Class HF |
| Number in class | 11 |
| Number | 1380-1390 |
| Delivered | 1927-1928 |
| First run | 1927 |
| Withdrawn | 1951 |
| Disposition | Retired |
In 1927 the South African Railways placed ten Class HF Modified Fairlie articulated steam locomotives with a 2-8-2+2-8-2 "Double Mikado" wheel arrangement in service. An eleventh one was placed in service in 1928.[1][3]
Contents |
The Class HF Modified Fairlie locomotive was designed by the South African Railways (SAR) under the direction of Colonel F.R. Collins, Chief Mechanical Engineer (CME) of the SAR from 1922 to 1929. Ten locomotives were built by Henschel and Son in 1926 and were numbered 1380 to 1389 when they were delivered in 1927. Another locomotive, number 1390, was built in 1927 and delivered by Henschel in 1928.[1][2][3]
The Class HF, designed for main line work, was larger and much heavier than the Class FC and Class FD Modified Fairlie branch line locomotives of 1924 and 1926. It was the Modified Fairlie equivalent of the Class GE 2-8-2+2-8-2 Garratt, which was similar in both size and mechanical respects. If the earlier classification practice for Modified Fairlie locomotives had been adhered to, it should therefore logically have been designated Class FE, but the inconsequent designation of Class HF for "Henschel Fairlie" was used instead. They had Walschaerts valve gear, bar frames and were superheated, but had round top fireboxes, unlike the earlier Modified Fairlie locomotives which had Belpaire fireboxes.[1][3][4]
As built, they were not successful, with the result that they were staged for some time while the Mechanical Engineer of the Durban workshops, G. Ramsay, carried out experiments with the blast pipe arrangement. After successful modification, their steaming capacity was improved to the extent that they could be placed in service. Like the earlier Modified Fairlies, they proved to be powerful locomotives but they were less successful than their Garratt equivalent.[1][3]
They suffered from the same shortcomings as their Class FC and Class FD predecessors. The long rigid frame resulted in severe overhang on sharp curves. The pivot bearings were subject to quite rapid wear since they carried a considerable additional load compared to those on the Garratt equivalent as a result of the water and coal bunkers that were mounted on the main frame instead of on the engine units. This resulted in increased maintenance and, as a consequence, increased operating cost. No more locomotives of the Modified Fairlie design were acquired by the SAR.[4]
The Class HF locomotives were placed in service on the Natal North Coast line and on the Witwatersrand. They were withdrawn from service by 1951.[1][3]
The main picture shows Class HF 1386, circa 1940.
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