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South African Class 23 4-8-2

From Alfawiki
South African Railways Class 23
Company typeSteam locomotive
IndustryRailway transport
Founded1938
FounderW.A.J. Day (Chief Mechanical Engineer)
Headquarters
South Africa
ProductsSteam locomotives


Template:Use South African English Template:Infobox locomotive

The South African Railways Class 23 4-8-2 represents a series of steam locomotives operated by South African Railways.

Between the years of 1938 and 1939, a total of 136 units of the Class 23 steam locomotives were introduced into service by South African Railways. This class holds the distinction of being the final and largest Mountain-type (4-8-2) locomotive developed by the South African Railways engineering team.

Manufacturers

The Class 23 4-8-2 Mountain steam locomotive was developed under the direction of W.A.J. Day, who served as Chief Mechanical Engineer (CME) of the South African Railways (SAR) between 1936 and 1939. Conceived as a versatile engine capable of running on 80 pounds per yard (40 kilograms per metre) rail, it was produced in two series by German manufacturers Berliner Maschinenbau and Henschel and Son. The initial 1938 order comprised twenty units, with Berliner constructing seven locomotives numbered from 2552 to 2558, while Henschel built thirteen, numbered from 2559 to 2571.

File:W.A.J. Day.jpg
W.A.J. Day

Due to the escalating political tensions in Europe, a substantial follow-up order for 116 locomotives was placed even before the delivery and evaluation of the first batch—a departure from SAR’s typical procedures. This preemptive procurement represented a record quantity for a new locomotive class prior to operational trials. In this second production run, Henschel manufactured 85 units numbered between 3201 and 3285, while Berliner produced 31 locomotives numbered from 3286 to 3316. The final engine from this order was delivered in August 1939, merely one month before the onset of the Second World War.

One Berliner-built locomotive, no. 3301, was assigned an unusual works number, receiving Berliner no. 10816 instead of the expected no. 11000, as the latter was reserved for the new Class 01.10 4-6-2 Pacific type locomotive destined for the German State Railways.

Characteristics

The Class 23 shared a strong resemblance in both design and power output to the Classes 15E and 15F locomotives. Initially planned with 66 inches (1,676 millimetres) diameter coupled wheels, this would have necessitated a newly designed boiler to accommodate the extended coupled wheelbase length. However, due to mounting political instability in Europe and the urgency it imposed, there was insufficient time to develop a new boiler design. Consequently, the existing Watson Standard no. 3B boiler was adopted, fitted with an elongated smokebox extended by 1 foot 6 inches (457 millimetres) to partly offset the shorter boiler length. This boiler type was part of a standardized range designed by A.G. Watson, Day’s predecessor as CME. To maintain tractive effort comparable to that of the Class 15E, boiler pressure was increased to 225 pounds per square inch (1,551 kilopascals), marking the highest pressure applied on SAR locomotives at that time; this was constrained by the SAR loading gauge which limited horizontal cylinder bore diameters to 24 inches (610 millimetres) using standard cylinder spacing.

Initially delivered without smoke deflectors, these locomotives were retrofitted after World War II with standard elephant ear smoke deflectors inspired by designs used by the Deutsche Reichsbahn.

The inner firebox featured steel construction and incorporated five arch tubes measuring 3 inches (76 millimetres) in diameter that supported the brick arch. Its rocking grate system included two drop-grates operated via a steam shaker mechanism. Following Watson Standard boiler conventions, the hopper-type ashpan was mounted on the main frames rather than on the boiler foundation ring, allowing for a 4 inches (102 millimetres) air gap all around. Cleaning was facilitated by fitted drench pipes, and a hand-operated sliding door was installed at the ashpan’s base.

To negotiate curves with a radius as tight as 300 feet (91 metres), several design adaptations were implemented: the leading coupled wheels were granted a total side-play of 1 inch (25 millimetres) within their horn blocks; intermediate coupled wheels had reduced flange thickness; and spherical bearings were incorporated at knuckle joints and crank pins of leading coupling rods. Moreover, partly due to adopting the shorter Watson Standard boiler, coupled wheel diameter was reduced from the originally planned 66 inches (1,676 millimetres) to 63 inches (1,600 millimetres), which shortened the coupled wheelbase and further improved maneuverability on sharp curves.

Tender

Designed for operation in the Karoo, where high-quality water sources are limited, these locomotives were fitted with exceptionally large Type EW tenders. These tenders, mounted on six-wheeled bogies, allowed for extended distances between watering stops or the ability to bypass inferior water supplies. At the time, they represented the largest tenders deployed in South Africa. Initially, their specifications included a water capacity of 10,000 imperial gallons (45,500 litres) and a coal capacity of 18 long tons (18.3 tonnes). However, due to axle load constraints, the water capacity had to be reduced to 9,200 imperial gallons (41,800 litres). This configuration was standard for the first set of twenty locomotives delivered.[1][2][3][4][5]

For the second delivery batch comprising 116 locomotives, alterations were made to the tender underframe to enhance weight distribution. Both tender pivot points were shifted 6 inches (152 millimetres) rearward, permitting an increased water capacity of 9,500 imperial gallons (43,200 litres) on these tenders. Although the overall length over couplers between locomotive and tender remained unchanged, the total wheelbase extended by 6 inches (152 millimetres), due to an increase in distance from the engine’s trailing axle to the first tender axle—from 10 feet (3,048 millimetres) to 10 feet 6 inches (3,200 millimetres).[1][2][4][5]

The tender wheels were equipped with clasp brakes actuated by four vacuum cylinders, complemented by a manual hand brake. Recognizing that a firegrate area of 63 square feet (5.9 square metres) could not be consistently managed by manual stoking—especially on extended journeys—a type H.T-1 mechanical stoker was installed. This stoker, produced by the Standard Stoker Company of America, had its engine mounted directly on the tender.[1][2][3]

Streamlining

In the 1930s, streamlining locomotives became a popular trend in Europe and the United States of America. There was consideration given to applying streamlining features to some Class 23 locomotives intended for service on the Cape mainline, prompting manufacturers to provide cost estimates. However, since streamlining would add approximately £500 per unit and increase locomotive weight by about 2 long tons (2.0 tonnes), the proposal was ultimately dismissed. This decision was influenced by the minimal performance gains at the official maximum goods train speed of 55 miles per hour (89 kilometres per hour) on Cape gauge, coupled with reduced accessibility for maintenance on streamlined locomotives.[1][2][3]

Locomotive naming

The tradition of assigning names to locomotives in South Africa can be traced back to the 0-4-2 engines of the Cape Town Railway and Dock Company from 20 March 1860, as well as the Natal Railway's 0-4-0WT Natal introduced on 13 May 1860, although this practice was infrequent. In 1945, the then Minister of Transport, the Honourable F. C. Sturrock MP, directed that certain Classes 15F and 23 locomotives be named after various South African cities and towns, with bilingual nameplates installed. These ornamental plates were mounted either on the sides of the smokebox or on the elephant ear smoke deflectors where applicable. A total of thirteen Class 23 locomotives received such names.

File:Class 23 no. 3300 Kroonstad Wing.JPG
Nameplate Kroonstad displayed on Class 23 no. 3300, positioned beside Class 15F no. 3044

Over time, some names were transferred to locomotives from other classes, with several eventually adorning Class 25NC engines. Additional names were introduced later; for instance, by 1969 locomotive no. 3229 carried the name Springs.

Service

Shortly after their introduction, this class became the primary source of traction on routes between Touws River and Beaufort West, as well as from De Aar to Welverdiend via Kimberley and Klerksdorp.

Initially, a limited number of Class 23 locomotives were briefly assigned to Braamfontein to haul the Union Limited and other express passenger services originating from Johannesburg to Cape destinations. Consequently, the Class 16DA and Class 16E units were relocated to Bloemfontein. Due to the electric turntable at Braamfontein being unable to accommodate these locomotives along with their extended Type EW tenders, engines arriving from Klerksdorp had to detach at Johannesburg station and proceed light engine to India Junction near Germiston, where they were turned using a triangular junction. As a result, these Braamfontein-based Class 23s were soon reassigned to the Cape Northern System, and Braamfontein received Class 15Fs which fit its turntable requirements.

Following the introduction of the newer Classes 25 and 25NC in 1953, Class 23 locomotives were redeployed to Bloemfontein to operate routes heading south towards Noupoort and Burgersdorp. Occasionally they serviced northern routes as far as Kroonstad and westward towards Kimberley; however, these duties were predominantly handled by Class 15Fs.

In response to increased ore transportation from Postmasburg to Durban during the late 1950s, caboose-working was introduced around 1959. Steam-powered block trains carrying manganese ore traveled from Postmasburg through Kimberley and Bloemfontein to Kroonstad, with four such loads dispatched daily to Maydon Wharf in Durban without interruption throughout the week. Four crews operated in pairs of Class 23 locomotives equipped with cabooses for crew accommodation on a rotating schedule lasting twenty-one days out of Bloemfontein. While shifts were intended to be eight hours on followed by eight hours off, crews generally agreed upon twelve-hour working periods.

Each caboose cycle commenced by collecting a set of thirty-four empty hopper wagons plus a guard's van in Bloemfontein, which were hauled through to Postmasburg with refueling at Kamfersdam near Kimberley. At Postmasburg, thirty-four loaded hopper wagons carrying approximately 2,700 tons along with a guard's van were picked up and transported continuously to Kroonstad. There, loads were reorganized into smaller segments weighing about fifteen hundred tons each for traversal over steep grades eastward toward Harrismith. The loaded wagons were exchanged for empties at Kroonstad before repeating the circuit. Refueling stops occurred at Postmasburg, Kamfersdam, Hamilton, and Kroonstad; water replenishment points included Kloofeind and Glen. Completing a full loaded-empty cycle took approximately two days, with crews managing around ten cycles during each three-week duty period. Caboose-working consistently involved pairs of Class 23 locomotives until approximately 1962 when the introduction of Class 25 condensers took over operations between Postmasburg and Kamfers Dam, leading to discontinuation of this practice. After electrification reached Postmasburg late in 1966, steam traction commenced only at Beaconsfield again; crew and locomotive changes reverted to traditional locations at Bloemfontein, Kroonstad, and Bethlehem.

Due to fatigue-induced cracks developing in their rolled steel bar frames measuring about 5 inches (127 millimetres) thick, Class 23 locomotives were withdrawn from mainline service significantly earlier than their contemporary counterparts like the similar Class 15F. All units had been retired by 1983; many contributed their large Type EW tenders to extend the operational range of Class 15F engines. Notably, at least one tender—belonging to no. 3209—was later converted into a water-only tender configuration.

Works numbers

The following table details the engine numbers, manufacturers, and corresponding works numbers for the Class 23 locomotives. According to the manufacturers' production records, all units were constructed in the year 1938.


Preservation

Out of the original fleet, two locomotives have been preserved:

Number Works Number THF / Private Ownership Leased / Current Owner Location Outside SOUTH AFRICA Notes
2556 Berliner 10742 Private Touws River Municipality
3300 Berliner 10999 THF Transnet Heritage Foundation Bloemfontein Locomotive Depot

Illustration

The featured image depicts Berliner-manufactured locomotive no. 2556, which was installed as a static display near the High School in Gideon Joubert Park, Touws River, commemorating the railway town’s centennial celebration in 1977. The locomotive was formally handed over to the municipality on 24 September 1977 by SAR’s chief executive, Dr. Kobus Loubser.

References

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  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 Cite error: Invalid <ref> tag; no text was provided for refs named SAR&H Jan 1947
  3. ↑ 3.0 3.1 3.2 Cite error: Invalid <ref> tag; no text was provided for refs named Paxton-Bourne
  4. ↑ 4.0 4.1 Cite error: Invalid <ref> tag; no text was provided for refs named Diagram-book 1
  5. ↑ 5.0 5.1 Cite error: Invalid <ref> tag; no text was provided for refs named Diagram-book 2

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