Power type Steam Serial number 26313-26412 | Order number L976 Model Class 24 | |
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Designer South African Railways
(Dr. M.M. Loubser) Builder North British Locomotive Company | ||
The South African Railways Class 24 2-8-4 of 1949 was a steam locomotive.
Contents
In 1949 and 1950, the South African Railways placed 100 Class 24 branchline steam locomotives with a 2-8-4 Berkshire type wheel arrangement in service.
Manufacturer
By the late 1940s, the South African Railways (SAR) still had a comparatively large mileage of 45 pounds per yard (22 kilograms per metre) track. In South West Africa, where most of the locomotive fleet consisted of Classes 6, 7, GC and GCA, there were still hundreds of miles of 4 1⁄4 pounds per yard (2.1 kilograms per metre) track. Considering the increasing age of these locomotives, the options were either to relay these tracks with 60 pounds per yard (30 kilograms per metre) rail or to obtain new light branchline locomotives, suitable for use on the existing track.
The Class 24 2-8-4 Berkshire type branchline steam locomotive was designed by Dr. M.M. Loubser, Chief Mechanical Engineer (CME) of the SAR from 1939 to 1949. The locomotives were built by North British Locomotive Company (NBL) of Glasgow, who delivered one hundred of them in 1949 and 1950, numbered in the range from 3601 to 3700. The cast engine main frames and the Buckeye bogies for the tenders were supplied by General Steel Castings of Eddystone, Pennsylvania.
One of these locomotives, no. 3675, was the 2,000th locomotive to be built by NBL for the SAR and, to commemorate this milestone, a ceremony was conducted in Cape Town to name the locomotive Bartolomeu Dias, after the famous Portuguese navigator who discovered the Cape of Good Hope in May 1488 and named it the Cape of Storms (Cabo das Tormentas). The ceremony was attended by the South African Minister of Transport and heads of departments of the SAR, as well as by the chairman and managing director of NBL.
Characteristics
The Class 24 had a one-piece cast-steel main frame, which was cast integrally with the cylinders, including the cylinder hind covers, smokebox support frame, stays and various brackets, all of which would normally be separate items, riveted or bolted onto the frames. Advantages of this arrangement are reduced maintenance and less time spent in shops. It was the first South African steam locomotive to be built using this technique.
They were built with Watson Standard no. 1 boilers, while their double hopper type ashpans were specially designed to clear the four-wheeled trailing bogies. Their specially designed Type MY tenders were similar in appearance to the Type MX and the North American Vanderbilt type tenders, with cylindrical water tanks. The tenders rode on three-axle Buckeye bogies to reduce the axle load and, along with the Type MX, became commonly known as Torpedo tenders.
The piston valves were actuated by Walschaerts valve gear and the standard SAR type steam reversing gear was arranged on the right-hand side. The engine and tender were both equipped with vacuum brakes and the engine's two 21 inches (533 millimetres) diameter vacuum cylinders were arranged outside the engine's frame and under the running boards, one on either side. The valve gear, brake gear and coupled wheel hubs were soft grease lubricated, while the bronze axle boxes had hard grease lubrication. The leading and trailing bogies were fitted with roller bearing axle boxes, while the tender's bogies used plain bearings.
Service
The Class 24 was built to replace the old Classes 6, 7 and 8 locomotives in branchline service on light rail. When they were introduced, an elaborate programme was drawn up to show on which systems and on what sections they were to be employed.
Most of them went to the South West Africa (SWA) System, where 55 of them would be in operation. From some time between 1955 and 1959, they were also employed on the Keetmanshoop-Walvisbaai section. They remained in that territory until 1961, when strengthening of the track and the complete dieselisation of the SWA System made them available to be employed elsewhere.
Some eventually also worked on the Selati line in the Transvaal Lowveld and, in 1969 and 1970, also briefly on the line from Hutchinson in the Karoo to Calvinia in the Hantam.
Other branchlines to be served by the Class 24 include Breyten to Lothair, Nylstroom to Vaalwater, Port Elizabeth to Alexandra and George to Knysna. As a relatively powerful locomotive, they were also useful as suburban locomotives, a role they served in on the Springs-Nigel commuter line until electrification. Heavy overhauls were done at Bloemfontein. The only province where they were unknown was Natal.
Preservation
They were withdrawn from service and retired in the mid-1980s. By 2010, preserved Class 24 locomotives included no. 3668, which served on the Outeniqua Choo Tjoe tourist line between Knysna and Mosselbaai until the operation was ceased in 2010, and no. 3655 Jenny (formerly named City of Cape Town) which is still based at Monument station in Cape Town and is being operated by volunteers of the Friends of Atlantic Rail. In Gauteng, no. 3664 Jo-Anna is still being operated around Pretoria by the Friends of the Rail.
No. 3620 is preserved in Cairns, having been exported to Australia in January 2001 for operation on the Kuranda Scenic Railway.
Illustration
The main picture shows no. 3655, the City of Cape Town, leaving Monument station in Cape Town on 8 August 2010. This locomotive was rechristened Jenny in 2011, in honour of the late Jenny Pretorius, a much respected South African steam preservationist.