South African Class 15F 4 8 2

Manufacturers

The Class 15F 4-8-2 Mountain type steam locomotive was designed by W.A.J. Day, Chief Mechanical Engineer (CME) of the South African Railways (SAR) from 1936 to 1939, based on the design of the Class 15E by his predecessor, A.G. Watson, and modified again by his successor, M.M. Loubser. It was built in five batches by four locomotive manufacturers in Germany and the United Kingdom over a period of eight years spanning the Second World War.

Lineage

The Class 15F represented the ultimate stage in a long history of development spanning thirty years. The first Class 15 4-8-2 tender loco­motive entered SAR service in 1914. It sported a 40 square feet (3.7 square metres) grate, a boiler pressure of 185 pounds per square inch (1,276 kilopascals), a maximum axle load of 16 long tons 10 hundredweight (16,760 kilograms) and 57 inches (1,448 millimetres) diameter coupled wheels. Later models incorporated major improvements in succession, until the Class 15CA was commissioned in 1926 with a 48 square feet (4.5 square metres) grate, a boiler pressure of 210 pounds per square inch (1,448 kilopascals), a maximum axle load of 17 long tons 15 hundredweight (18,030 kilograms) and 60 inches (1,524 millimetres) diameter coupled wheels.

Characteristics

The Class 15F locomotive was similar to its predecessor Class 15E, but it was built with Walschaerts valve gear, as specified by Day, who was not a protagonist of Rotary Cam Poppet valve gear. This and some other differences led to it being classified 15F. The locomotives used Stone's electric lighting, with a 150 watt Tonum E type headlight, cab lighting which included a light over the reversing controls, a bunker light and rear headlights on the tender. The locomotive was capable of traversing curves of 275 feet (84 metres) radius with ³⁄₄ inch (19 millimetres) widening.

The Class 15F was delivered with a Watson Standard no. 3B boiler and a Watson cab. During the 1930s, Day's predecessor as CME, A.G. Watson, designed a standard boiler type as part of his standardisation policy. Many serving locomotives were reboilered with these Watson Standard boilers and in the process most of them were also equipped with Watson cabs, with their distinctive slanted fronts compared to the conventional vertical fronts of their original cabs. New locomotives which were acquired in the Watson era and later, such as the Class 15F, were built with such boilers and cabs.

To fit within the loading gauge, the Watson Standard no. 3B boiler was domeless. The maximum height of the locomotive was 12 feet 11 ¹⁄₂ inches (3,950 millimetres), the maximum width 10 feet (3,048 millimetres) and the length over coupler faces 73 ft 5 ¹⁵⁄₁₆ in (22,401 mm).

The cylinder barrels had cast iron liners. The valve gear, brake gear and the hubs on the coupled wheels were fitted with soft grease lubricating nipples, while the bronze axle boxes and connecting and coupling rods had hard grease lubrication. The leading and trailing wheels were fitted with roller bearings. The axle boxes and motion were similar to those of the Classes 15CA and 23 and were interchangeable in most cases. The weight of the reciprocating parts on each side of the engine was 1,273 pounds (577 kilograms), of which 20% was balanced to ensure that the hammer blow per wheel does not exceed 1 long ton 12 hundredweight (1.6 tonnes) at 55 miles per hour (89 kilometres per hour) and with the overbalance equally divided on all the coupled wheels.

Pre-war models

The pre-war Class 15Fs were manually stoked and were delivered without smoke deflectors. The original 21 Berliner- and Henschel-built engines remained hand-fired for the full duration of their working lives. On the pre-war NBL-built engines, on the other hand, provision was made in the design to later convert them to mechanical stoking. A mechanical stoker was tested on no. 2923 before the remaining locomotives of that group were all equipped with such stokers by the late 1940s. Their brake systems consisted of steam brakes on the engines and vacuum brakes on the tenders.

One of the Henschel-built locomotives, no. 2916, is documented as having a lighter all-up weight and different axle loads than the rest of the engines from the same batch, although its adhesive weight is more than a ton heavier. While sources are silent on the reason for the differences, it is known that this engine was oil-fired, although it is not clear whether it was delivered as an oil-burner or modified post-delivery.

Post-war models

The post-war locomotives were built to the design and specifications of Doctor M.M. Loubser, who succeeded Day as CME in 1939. His specifications included mechanical stokers, smoke deflectors, vacuum brakes on the coupled wheels as well as the tenders, with two 24 inches (610 millimetres) diameter brake cylinders on the engine and two 21 inches (533 millimetres) diameter cylinders on the tender.

The engine's vacuum brake cylinders were fitted outside the main frames under the running boards on each side, between the second and third pairs of coupled wheels. The vacuum brake operated automatically whenever the train brakes were applied. The use of vacuum braking instead of steam braking became standard practice on locomotives from 1944 onwards and was welcomed by SAR drivers, who were always reluctant to make use of steam brakes for fear of skidding the coupled wheels. In practice, the trigger on the steam brake attachment, to isolate the proportional device which admitted steam to the brake cylinder automatically upon the application of the vacuum brake, was invariably wedged down with a wooden peg by drivers to eliminate the steam brake entirely.

Loubser also modified the leading bogie to have swing links with three-point suspension, which eliminated the side control springs which were used on earlier versions. As a unit, the modified bogie was interchangeable with those of earlier versions and with those of the Classes 15E and 23. The leading bogie had a side-play of 8 inches (203 millimetres), while the trailing Bissel truch had a side-play of 9 ³⁄₈ inches (238 millimetres).

The engines from Beyer, Peacock were war-time austerity models on which planished steel boiler lagging was replaced by ordinary steel lagging, while cosmetic dressing items like stainless steel lagging bands, chrome-plated handrails and rounded corners on the front of the firebox lagging were absent or replaced by unplated items. While the boiler barrels of the pre-war engines were of nickel steel, the austerity locomotives had boiler barrels made of carbon steel, with steel plates of ¹⁄₁₆ inch (2 millimetres) greater thickness. When it was subsequently found that the increased thickness was unnecessary, ¹³⁄₁₆ inch (21 millimetres) thick carbon steel plates were used on later orders, the same thickness as earlier used with nickel steel plates, which resulted in a desirable reduction in axle loads.

Like the pre-war NBL-built engines, the early post-war locomotives, built by BP and NBL in 1944 and 1945, were delivered with Type JT tenders, which had a 14 long tons (14.2 tonnes) coal capacity and a 6,000 imperial gallons (27,300 litres) water capacity. As delivered, they were arranged for manual stoking, but with provision made in their design for their subsequent conversion to mechanical stoking. All these locomotives were equipped with mechanical stokers post-delivery.

The locomotives in the final batch of 100 which were received from NBL in 1947 and 1948, numbers 3057 to 3156, were delivered new complete with mechanical stokers and smoke deflectors. These engines were delivered with Type ET tenders, which also had a 14 long tons (14.2 tonnes) coal capacity, but a smaller 5,620 imperial gallons (25,500 litres) water capacity to accommodate the mechanical stoker mechanism, while its empty weight was 1,232 pounds (559 kilograms) more due to the additional stoking equipment. These appear to have been the only differences between the Types JT and ET tenders. Apart from these differences, the post-war locomotives were identical to the earlier ones. Elephant ear smoke deflectors were later installed on the pre-war locomotives as well.

Locomotive naming

Although the naming of locomotives in South Africa dates back to the Cape Town Railway and Dock Company's 0-4-2 locomotives of 20 March 1860 and the Natal Railway's 0-4-0WT Natal of 13 May 1860, it was rarely done. In 1945, the Minister of Transport at the time, the Honourable F.C. Sturrock MP, instructed that a number of Classes 15F and 23 engines should be named after various South African cities and towns and fitted with suitable nameplates in both official languages. The decorative plates were fitted to the sides of the smokebox, or to the elephant ears smoke deflectors of engines which were so equipped. Twelve Class 15F locomotives were named.

In later years, some of these name plates migrated to other engines and classes, with several eventually ending up on Classes 23 and 25NC locomotives.

Service

While the Class 15F was used predominantly in the Orange Free State and Western Transvaal, it also saw service in every system country-wide, including Garratt territory in Natal, where it was used on the line from Newcastle to Utrecht. The Class also briefly served on the Cape Eastern system, when it worked out of East London in the early 1960s.

Some briefly served outside South Africa's borders. In 1978, six Class 15Fs were hired to Rhodesia Railways, but they were returned nine months later and replaced by Class GMAM Garratts.

When the Class 23 was retired, many of the Class 15F locomotives which were equipped with mechanical stokers inherited their huge twelve-wheel Type EW tenders which, apart from increasing their range with its larger fuel and water capacity, also greatly enhanced their appearance. In later years, when the Class 15F was relegated to heavy shunting and local work, many of the locomotives had their mechanical stokers removed.

Preservation

As would be expected, given its usefulness and the large quantity placed in service with the SAR, several Class 15F locomotives have survived into preservation.

The Pretoria-based steam heritage club Friends of the Rail (FOTR) possesses two locomotives of this class, numbers 3094 and 3117.

The Germiston-based Reefsteamers has three Class 15F locomotives in its stable, no. 2914 Spikkels, a hand-fired version, no. 3016 Gerda and no. 3046 Janine. The latter was the club's only operational 15F as of February 2016. The boiler certificate was due to expire by July 2016, which took no. 3046 out of service for a while. The club was, however, already in the process of restoring no. 3052 Avril, the locomotive which David Shepard OBE FRSA FGRA traded a painting for during the 1991 steam festival. The locomotive is ultimately in the care of Sandstone Estates, but a refurbishment contract was awarded to Reefsteamers late in 2015.

Beyer, Peacock-built no. 2994 is preserved at the Worcester Museum at Kleinplasie, where it is displayed astride the locomotive inspection pit in the old locomotive shed.

In 2006, NBL-built no. 3007 was returned to its builder's home city, Glasgow in Scotland, where it was initially put on static display in George Square for fundraising purposes by the North British Locomotive Preservation Group. The move of no. 3007 from storage in the Bloemfontein locomotive depot to Glasgow was recorded in Season 3 of the television documentary series Monster Moves in 2008. The locomotive was originally to have been trucked to Durban by Moveright International, but the transporter was not capable of carrying the locomotive. Instead, it was towed by rail on a two-day journey across the country, with ten flat wagons used to augment the braking capacity of the locomotives which hauled the Class 15F. The locomotive now resides in the Glasgow Museum of Transport's collection at the new Riverside Museum.

Commemoration

A 40c postage stamp, depicting a Class 15F locomotive, was one of a set of four commemorative postage stamps which were issued by the South African Post Office on 27 April 1983, to commemorate the steam locomotives of South Africa which were rapidly being withdrawn from service at the time. The artwork and stamp design was by the noted stamp designer and artist Hein Botha. The particular locomotive depicted was NBL-built Class 15F no. 2954. The outline of a traditional SAR locomotive number plate was used as a commemorative cancellation for De Aar on the date of release.

Works numbers

The table shows the Class 15F engine numbers, builders, years built and works numbers.

Illustration

The main picture shows pre-war NBL-built no. 2940 "Lynette", with an ex Class 23 type EW tender, at speed near Princess station on the Johannesburg-Magaliesburg line on 6 April 1992.