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South African Class 15CA 4-8-2

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South African Railways Class 15CA
Company typeSteam locomotive
IndustryRail transport
Founded1926
Headquarters
South Africa
ProductsSteam locomotives

South African Railways Class 15CA 4-8-2 Steam Locomotive

In 1926, the South African Railways introduced the Class 15CA steam locomotives featuring a 4-8-2 Mountain wheel configuration. Initially, a batch of 23 units was commissioned and brought into operation. Subsequently, an additional 61 locomotives were procured and delivered between 1929 and 1930 from three different manufacturers.

Class 15C Redesign

File:Col F.R. Collins DSO.jpg
Col F.R. Collins DSO

Shortly after the twelve Class 15C Big Bill 4-8-2 Mountain locomotives, supplied by Baldwin Locomotive Works in 1925, entered service, it became apparent that the frames beneath the front section of the firebox were prone to cracking, requiring extensive repairs.[1][2]

To address this issue, Col F.R. Collins DSO, who was then the Chief Mechanical Engineer (CME) of South African Railways (SAR), developed an updated design for a nearly identical locomotive. This revision featured frames shortened to just ahead of the firebox and expanded beneath it using a bridle casting.[1]

Manufacturers

The initial series of 23 locomotives reflecting this updated design were constructed by the American Locomotive Company (ALCO) for the SAR. Delivered in 1926, these engines bore numbers from 2039 to 2059, as well as 2072 and 2073, and were classified as Class 15CA. The suffix "A" is believed to denote ALCO as the manufacturer, diverging from the usual SAR practice where such letters indicated variant versions of existing locomotive classes.[1][2][3][4]

Meanwhile, the earlier Baldwin-built Class 15C locomotives were redesignated as Class 15CB without clear justification, since the "B" simply identified Baldwin as the builder rather than signifying a branchline variant as was typical.[4]

Between 1929 and 1930, an additional 61 Class 15CA units were procured in four separate consignments from three different manufacturers. Except for the final batch, all were constructed with 23 inches (584 millimetres) bore cylinders, consistent with the ALCO-built engines.[2]

  • In 1929, Baldwin Locomotive Works in the USA delivered four locomotives numbered from 2074 to 2077.[2]
  • Also in 1929, Società Italiana Ernesto Breda of Milan, Italy (now part of AnsaldoBreda), supplied ten locomotives numbered between 2801 and 2810.[2][4]
  • That same year, the North British Locomotive Company (NBL) manufactured and delivered twenty-nine units numbered from 2811 to 2839.[2][5]
  • The last eighteen Class 15CA locomotives were also produced by NBL in 1929 but delivered in 1930. These final units featured larger 24 inches (610 millimetres) bore cylinders and trailing wheels with increased diameter.[2][5]

Characteristics

Aside from the redesigned frame beneath the firebox, these locomotives closely resembled the original Class 15C in both size and external design. They were equipped with Coale pop safety valves, a Schmidt superheater system, and a combustion chamber within the firebox that incorporated flexible side stays along with water siphon arch tubes. Their coupled wheel axle boxes, crank pins, and connecting rod big ends operated with grease lubrication. These engines were paired with Type KT tenders, capable of carrying 14 long tons (14.2 tonnes) of coal and 6,000 imperial gallons (27,300 litres) of water.[2][1]

Retyring

Originally, the locomotives were equipped with coupled wheels measuring 57 inches (1,448 millimetres) in diameter and operated with boiler pressures set at 200 pounds per square inch (1,379 kilopascals). Over time, all coupled wheels were upgraded to a larger diameter of 60 inches (1,524 millimetres). To offset the reduction in tractive force caused by the increased wheel size, the boiler pressure was raised from 200 to 210 pounds per square inch (1,379 to 1,448 kilopascals) through adjustments to the safety valve settings. This enhancement allowed these versatile mixed-traffic engines to efficiently manage the fastest passenger services on mainline routes.

Furthermore, locomotives initially built with cylinders having a bore of 23 inches (584 millimetres) underwent reaming to enlarge the bore to 24 inches (610 millimetres).

When fitting larger tyres on the coupled wheels, the original tyres were retained and machined down on the wheel centers to act as liners. The new tyres were then shrunk over these liners. Additionally, the leading coupled wheels, which were originally flangeless, were modified by adding flanges during this retyring process. The practice of increasing coupled wheel diameter, adjusting wheel spacing, and other related modifications began under Chief Mechanical Engineer A.G. Watson's tenure and continued under his successors. To compensate for diminished tractive effort resulting from larger wheels, boiler pressure was increased or larger cylinders installed, or both, depending on requirements. This strategy led to greater distances between major overhauls, reduced repair costs per mile, and locomotives capable of higher operational speeds.

Reboilering

In the early 1940s, three locomotives from the Class 15CB and Class 15CA series received new boilers numbered between 9504 and 9506. These replacement boilers maintained similar dimensions to the originals but featured a revised tube configuration designed by Dr. M.M. Loubser, who was CME at that time. Despite these upgrades, the reboilered engines retained their original classification.

South African Railways

File:SAR Class 15CA 2828 (4-8-2) ID.JPG

The Class 15CA locomotives initially operated on the mainline connecting Cape Town and Kimberley. Subsequently, like their Class 15CB counterparts, they were reassigned to Bloemfontein. From this base, they served extensively throughout the Free State region before being transferred to the Eastern Transvaal network. There, their operations extended from Pretoria northwards to Pietersburg, eastwards to Tzaneen, and further north to Messina near the Rhodesian border. Additional units worked out of Witbank and Breyten.

During the early 1960s, several units joined the Class 15CB fleet on the National North Coast line. Their duties included hauling night and day passenger trains between Empangeni on the northern coast line and also passenger services connecting Kelso on the southern coast line. By 1983, all had been relocated to the Cape Northern system operating routes from Beaconsfield in Kimberley northward to Mafeking and southward to De Aar. Ultimately, close to forty locomotives ended their service as heavy shunting engines at Kaserne and Germiston in Johannesburg, where they replaced both the Class 12AR and Class S1 classes.

The locomotive numbered 2828 of Class 15CA is currently preserved as a static exhibit at Gospel Express, located at Vinkrivier Station along R60 in Robertson, Western Cape, South Africa. It forms part of an eleven-coach display serving as accommodation for the Gospel Express Christian Centre.

Industry

A total of three Class 15CA locomotives were transferred to industrial operations. Units 2807 and 2839 initially went to Dunn's Locomotive Works before being acquired by Rustenburg Platinum Mines. Locomotive number 2811 was assigned to South Witbank Colliery, where it operated as their no. 4.

Works numbers

Presented below is a table detailing the Class 15CA locomotives, including their SAR numbers, manufacturers, production years, and respective builders' serial numbers. The colour indicators adjacent to the engine numbers correspond to the three distinct axle load categories for the various Class 15CA production batches, as outlined in the specifications table.

... [table continues with same format for remaining entries] }

Preservation

Number Works Number THF / Private Leaselend / Owner Present Location Outside South Africa ?
2039 ALCO 66986 THF/Private MISLPT (Michael Barclay) Krugersdorp Locomotive Depot Ownership Status Uncertain
2040 ALCO 66987 THF/Private MISLPT (Michael Barclay) Krugersdorp Locomotive Depot Ownership Status Uncertain
2041 ALCO 66988 THF/Private MISLPT (Michael Barclay) Krugersdorp Locomotive Depot Ownership Status Uncertain
2055 ALCO 67005 THF Rustenburg Station
2056 ALCO 67003 THF Reefsteamers Germiston Locomotive Depot
2077 BAL 60831 THF/Private MISLPT (Michael Barclay) Krugersdorp Locomotive Depot Ownership Status Uncertain
2802 BREDA 2237 THF Esselenpark Railway College
2803 BREDA 2238 THF/Private MISLPT (Michael Barclay) Krugersdorp Locomotive Depot Ownership Status Uncertain
2804 BREDA 2239 THF Esselenpark Railway College
2820 NBL 23783 THF/Private MISLPT (Michael Barclay) Krugersdorp Locomotive Depot Ownership Status Uncertain
2825 NBL 23788 THF Krugersdorp Locomotive Depot
2828 NBL 23791 THF Gospel Express Vink Station
2833 NBL 23796 THF Krugersdorp Locomotive Depot
2836 NBL 23799 THF Krugersdorp Locomotive Depot
2850 NBL24018 THF Wonder Steam Trains Hermanstad Depot
2853 NBL24021 THF Krugersdorp Locomotive Depot

Illustration

The featured image depicts Breda-manufactured no. 2802, positioned as a school guard at Esselen Park, the Transnet School of Rail located in Kaalfontein, Gauteng, on the date of September 21, 2009.

References

  1. ↑ 1.0 1.1 1.2 1.3 Cite error: Invalid <ref> tag; no text was provided for refs named Holland 2
  2. ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 Cite error: Invalid <ref> tag; no text was provided for refs named SAR&H May 1946
  3. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named Paxton-Bourne
  4. ↑ 4.0 4.1 4.2 Template:Durrant-Twilight
  5. ↑ 5.0 5.1 North British Locomotive Company works list, compiled by Austrian locomotive historian Bernhard Schmeiser

External links

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