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South African Class 23 4-8-2
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In 1938 and 1939 the South African Railways placed one hundred and thirty-six Class 23 steam locomotive
Steam locomotive
A steam locomotive is a railway locomotive that produces its power through a steam engine. These locomotives are fueled by burning some combustible material, usually coal, wood or oil, to produce steam in a boiler, which drives the steam engine...

s in service. The Class 23 was the last and the largest 4-8-2
4-8-2
Under the Whyte notation for the classification of steam locomotives, 4-8-2 represents the wheel arrangement of four leading wheels on two axles , eight powered and coupled driving wheels on four axles, and two trailing wheels on one axle...

 Mountain locomotive to be designed by the South African Railways.

Manufacturers

The Class 23 4-8-2 steam locomotive was designed by W.A.J. Day, Chief Mechanical Engineer (CME) of the South African Railways (SAR) from 1936 to 1939. It was intended as a general utility locomotive capable of operating on 80 lb/yd rail, and was built in two batches by Berliner Maschinenbau
Berliner Maschinenbau
Berliner Maschinenbau AG was a German manufacturer of locomotives.The factory was founded by Louis Victor Robert Schwartzkopff on 3 October 1852 as Eisengießerei und Maschinen-Fabrik von L. Schwartzkopff in Berlin ....

 and Henschel and Son
Henschel & Son
Henschel & Son was a German company, situated in Kassel, best known during the 20th century as a maker of transportation equipment, including locomotives, trucks, buses and trolleybuses, and armoured fighting vehicles and weapons....

 in Germany. The original order in 1938 was for twenty locomotives, of which Berliner built seven, numbers 2552 to 2558, and Henschel thirteen, numbers 2559 to 2571.

The urgency brought about by the rapidly deteriorating political climate in Europe at the time led to a further one hundred and sixteen locomotives being ordered even before the first batch could be delivered and tested. Of these, Henschel built eighty-five, numbers 3201 to 3285, and Berliner thirty-one, numbers 3286 to 3316. The last locomotive of this second order was delivered in August 1939, just one month before the outbreak of World War II.

Locomotive number 3301 received an out of sequence works number, Berliner 10816 instead of 11000, since works number 11000 was reserved for a new 4-6-2 Pacific type locomotive for the German State Railways. The table shows the Class 23 running numbers, builders and works numbers. On the builders’ works lists all the locomotives are recorded as having been built in 1938.

Watson Standard boiler

As originally intended, the locomotive would have had 66 inches (1,676.4 mm) driving wheels, which would have required a newly designed boiler to accommodate the extra length. The increasing political turmoil in Europe and the resulting urgency, however, prohibited time being spent on designing a new boiler. As a result the existing Watson Standard no. 3B boiler was incorporated in the design, with an extra long smokebox to partially compensate for the shorter boiler. This boiler was one of the range of standard type boilers designed by Day’s predecessor as CME, A.G. Watson, as part of the latter’s standardisation policy.

Driving wheel diameter

In order to enable them to negotiate 300 feet (91.4 m) radius curves, the leading driving wheels were given a 1 inches (25.4 mm) side-play. In addition, largely also as a result of the decision to use the shorter Watson Standard boiler, it was decided to reduce the driving wheel diameter from 66 inches (1,676.4 mm) to 63 inches (1,600.2 mm), which shortened the coupled wheelbase and would further ease passage on sharp curves.

These decisions appear to have been taken at quite a late stage, since the cylinders were cast to suit the larger wheel diameter. To compensate for the decreased wheel diameter, the maximum boiler pressure was raised to 225 pound per square inches (1,551.3 kPa), at the time the highest yet used on the SAR.

Tender

Since these locomotives were intended for working in the Karoo where good quality water is a scarce resource, they were equipped with very large tenders with a high water capacity that rode on six wheeled bogies. They were the largest tenders to have been used in South Africa up to that time and as designed, they would have had a water capacity of 10000 gallons (45,460.9 l).

Axle load restrictions, however, led to the water capacity being reduced to 9200 gallons (41,824 l) for the first order of twenty locomotives. This was increased to 9500 gallons (43,187.9 l) for the second order of one hundred and sixteen. Four vacuum cylinders operated clasp brakes on all tender wheels.

Streamlining

During the 1930s the streamlining of locomotives was fashionable in Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

 and the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

. It was proposed to adopt streamlining on some of the Class 23 locomotives, but investigation showed that it would increase the cost by £500 per locomotive and increase the weight by approximately 2 long tons (2 t). Those factors, coupled to the negligible performance benefit of streamlining at normal goods train speeds as well as the reduced accessibilty of working parts on a streamlined locomotive, led to this idea being abandoned.

Service

In general appearance and power the Class 23 locomotive is very similar to the Class 15E
South African Class 15E 4-8-2
Between 1935 and 1937 the South African Railways placed forty-four Class 15E steam locomotives with a 4-8-2 Mountain wheel arrangement in service. -Manufacturers:...

 and 15F
South African Class 15F 4-8-2
The Class 15F was the most numerous steam locomotive class in South African Railways service. Between 1938 and 1946 two hundred and fifty-five of these steam locomotives with a 4-8-2 Mountain wheel arrangement were placed in service.-Manufacturers:...

. In their first few years of service the Class 23 fleet formed the bulk of the motive power on the lines from Touws River
Touws River (town)
Touws River is a small railway town of 6,800 people in the Western Cape province of South Africa. It is located on the river of the same name, about north-east of Cape Town.-History:...

 to Beaufort West
Beaufort West
Beaufort West is a town in the Western Cape province in South Africa. It is the largest town in the arid Great Karoo region, and forms part of the Beaufort West Local Municipality, with 37 000 inhabitants in 2001....

 and from De Aar to Klerksdorp via Kimberley
Kimberley, Northern Cape
Kimberley is a city in South Africa, and the capital of the Northern Cape. It is located near the confluence of the Vaal and Orange Rivers. The town has considerable historical significance due its diamond mining past and siege during the Second Boer War...

.

Electrification of the section between Kimberley and Klerksdorp and, almost simultaneously, the arrival of the new Class 25
South African Class 25 4-8-4
Between 1953 and 1955 the South African Railways placed ninety Class 25 condensing steam locomotives with a 4-8-4 Northern wheel arrangement in service...

 and Class 25NC
South African Class 25NC 4-8-4
Between 1953 and 1955 the South African Railways placed fifty Class 25NC steam locomotives with a 4-8-4 wheel arrangement in service. The Class 25NC is the non condensing version of the Class 25 condensing locomotive, of which ninety were placed in service at the same time...

 in 1953 caused them to be transferred to Bloemfontein
Bloemfontein
Bloemfontein is the capital city of the Free State Province of South Africa; and, as the judicial capital of the nation, one of South Africa's three national capitals – the other two being Cape Town, the legislative capital, and Pretoria, the administrative capital.Bloemfontein is popularly and...

, to work from there to Kimberley to the west and Kroonstad
Kroonstad
Kroonstad is the third-largest town in the Free State province of South Africa, and lies two hours drive from Gauteng. In the 1991 census it had a population of 110,963...

 to the north.

Due to metal fatigue cracks that developed in their 5 inches (127 mm) thick rolled steel bar frames, they were withdrawn from main line service considerably earlier than the similar Class 15F. They were all retired by 1983, many of them in the process donating their large Type EW tenders to increase the range of the Class 15F
South African Class 15F 4-8-2
The Class 15F was the most numerous steam locomotive class in South African Railways service. Between 1938 and 1946 two hundred and fifty-five of these steam locomotives with a 4-8-2 Mountain wheel arrangement were placed in service.-Manufacturers:...

. At least one of these tenders, that of number 3209, was later rebuilt to a water only tender.

Gallery

The main picture shows Berliner built number 2556, which was plinthed next door to the High School in Gideon Joubert park in Touws River on occasion of that Railway town’s centenary in 1977. It was officially presented to the town by SAR chief executive Dr. Kobus Loubser on 24 September 1977.


See also

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