South African Class 12B 4-8-2 - AbsoluteAstronomy.com

In 1920 the South African Railways placed thirty Class 12B 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 with a 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 wheel arrangement in service.

Manufacturer

The Class 12

South African Class 12 4-8-2

Between April 1912 and 1922 the South African Railways placed altogether forty-six Class 12 steam locomotives with a 4-8-2 Mountain wheel arrangement in goods train service.-Manufacturers:...

was the first locomotive design to originate from the newly established South African Railways (SAR) in 1912. It was in effect an enlarged version of SAR Chief Mechanical Engineer (CME) D.A. Hendrie’s already successful Class 3B

South African Class 3B 4-8-2

In 1912 the South African Railways took delivery of ten Class 3B steam locomotives with a 4-8-2 Mountain wheel arrangement that had been ordered by the Natal Government Railways the year before.-Manufacturer:...

, also built with plate frames, Walschaerts valve gear and Belpaire firebox

Belpaire firebox

The Belpaire firebox is a type of firebox used on steam locomotives. It was invented by Alfred Belpaire of Belgium. It has a greater surface area at the top of the firebox, improving heat transfer and steam production...

es.

In May 1920 an additional thirty locomotives, built to the Class 12 design, were delivered from Baldwin Locomotive Works

Baldwin Locomotive Works

The Baldwin Locomotive Works was an American builder of railroad locomotives. It was located in Philadelphia, Pennsylvania, originally, and later in nearby Eddystone, Pennsylvania. Although the company was very successful as a producer of steam locomotives, its transition to the production of...

in the United States

United States

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

. Even though they were very similar to the second and subsequent orders of the Class 12, they were classified separately as Class 12B.

Classification

The separate classification has been ascribed to the fact that the wheelbase of the leading bogie was 2 inches (50.8 mm) longer than on the original Class 12 locomotives, but this was probably not the reason, keeping in mind that only the first eight out of altogether forty-six Class 12 locomotives were built with leading bogies with a 6 feet (1.829 m) wheelbase while the other thirty-eight all had leading bogies with a 6 in 2 in (1.88 m) wheelbase, the same as the Class 12B. More likely the separate classification was simply based on the fact that the Class 12 was British built while the Class 12B was American built.

The Baldwin works numbers did not run consecutively for the whole order and are set out in the table.

Class 12B 4-8-2
Works numbers
SAR no.	Works no.
1931	52476
1932	52558
1933	52559
1934	52583
1935	52584
1936	52649
1937	52650
1938	52651
1939	52690
1940	52691
1941	52692
1942	52693
1943	52712
1944	52713
1945	52723
1946	52724
1947	52754
1948	52755
1949	52756
1950	52757
1951	52758
1952	52759
1953	52760
1954	52761
1955	52762
1956	52763
1957	52764
1958	52765
1959	52766
1960	52767

Watson Standard boilers

During the 1930s many serving locomotives were reboilered with a standard boiler type designed by then CME A.G. Watson as part of his standardisation policy. Such Watson Standard reboilered locomotives were reclassified by adding an "R" suffix to their classification.

All thirty Class 12B locomotives were eventually reboilered with Watson Standard no. 2 boilers. In the process they were also equipped with Watson cabs, with their distinctive slanted fronts, compared to the conventional vertical fronts of their original cabs. Upon reboilering the original reason for the separate classification was ignored and, instead of becoming Class 12BR, the reboilered locomotives were reclassified to Class 12R along with the reboilered Class 12

South African Class 12 4-8-2

Between April 1912 and 1922 the South African Railways placed altogether forty-six Class 12 steam locomotives with a 4-8-2 Mountain wheel arrangement in goods train service.-Manufacturers:...

locomotives.

An obvious visual difference between an original and a Watson Standard reboilered locomotive is usually a rectangular regulator cover just to the rear of the chimney on the reboilered locomotive. In the case of the Class 12B locomotives two even more obvious visual differences are the Watson cab and the absence of the Belpaire firebox

Belpaire firebox

hump between the cab and boiler on the reboilered locomotives.

South African Railways

They were placed in service on the Cape Midlands, working on the main line out of Port Elizabeth, where they largely remained until being withdrawn from service. Even though they were not designed to be mixed traffic locomotives, they saw service on both passenger and goods working.

Industrial

For some reason few Class 12Rs ended up in industrial service, despite their evident suitability for such work. Of the ex Class 12B locomotives, only number 1936 ended up in private service, first sold to Enyati Colliery and later becoming Western Holdings Gold Mine’s number 8.

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