In 1904 the Cape Government Railways

Cape Government Railways

The Cape Government Railways was the government-owned railway operator in the Cape Colony from 1874 until the creation of the South African Railways in 1910.-Private railways:...

 placed its last two Class 6 4-6-0

4-6-0

Under the Whyte notation for the classification of steam locomotives, 4-6-0 represents the wheel arrangement of four leading wheels on two axles in a leading truck, six powered and coupled driving wheels on three axles, and no trailing wheels. This wheel arrangement became the second-most popular...

 bar framed 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. In 1912, when they were assimilated into the South African Railways, they were renumbered and reclassified to Class 6L.

Manufacturer

The Class 6 4-6-0 locomotive was designed at the Salt River works of the Cape Government Railways (CGR) at the same time as the Class 7

South African Class 7 4-8-0

In 1892 the Cape Government Railways placed six Class 7 steam locomotives with a 4-8-0 Mastodon wheel arrangement in service and between 1892 and 1893 another thirty-two were acquired. They were initially placed in service on the Cape Midland System, but were later distributed between the Cape...

 4-8-0

4-8-0

Under the Whyte notation for the classification of steam locomotives, 4-8-0 represents the wheel arrangement of four leading wheels on two axles , eight powered and coupled driving wheels on four axles, and no trailing wheels. The type was nicknamed the Mastodon or Twelve-wheeler in North America....

. While the Class 7 was conceived primarily as a goods locomotive, the Class 6 was intended to be its fast passenger service counterpart.

The CGR placed its last order for two Class 6 locomotives with Neilson, Reid and Company in 1903. In that same year Scottish locomotive builders Sharp, Stewart and Company and Dübs and Company

Dûbs and Company

Dübs & Co. was a locomotive works in Glasgow, Scotland, founded by Henry Dübs in 1863 and based at the Queens Park Works in Polmadie. In 1903 it became part of the North British Locomotive Company.-Preserved locomotives:...

 merged with Neilson, Reid to form the North British Locomotive Company

North British Locomotive Company

The North British Locomotive Company was created in 1903 through the merger of three Glasgow locomotive manufacturing companies; Sharp Stewart and Company , Neilson, Reid and Company and Dübs and Company , creating the largest locomotive manufacturing company in Europe.Its main factories were...

 (NBL). The two locomotives, Neilson, Reid works numbers 6324 and 6323, built at the Hyde Park works of the former Neilson, Reid, were therefore delivered with NBL works numbers 15889 and 15888.

Characteristics

The two locomotives in this order were experimental and were the first South African locomotives to have piston valves and superheater

Superheater

A superheater is a device used to convert saturated steam or wet steam into dry steam used for power generation or processes. There are three types of superheaters namely: radiant, convection, and separately fired...

s. The pistons, with a bore of 18.5 inches (469.9 mm), were the largest yet used on the Class 6. Like other second generation Class 6 locomotives with bar frames, they had high running boards without driving wheel fairings. They were delivered in 1904 and numbered 909 and 910 for the Western System of the CGR.

Schmidt superheater

While in later superheater designs the superheater elements were passed down the boiler flues, the Schmidt

Wilhelm Schmidt (engineer)

Wilhelm Schmidt, known as Hot Steam Schmidt was a German engineer and inventor who achieved the breakthrough in the development of superheated steam technology for steam engines....

 superheater installed in these two locomotives was of the smokebox type with the tubes arranged around the shell of the smokebox. To ensure that the superheater tubes received ample heat, a large flue of 10.75 inches (273.1 mm) diameter was installed between the firebox and the front tube plate, where it connected to the casing of the superheater. In the smokebox it was necessary to provide a clearing chute beneath the smokebox where the flue joined the casing in order to prevent it from becoming clogged with cinders. Just forward of the blast pipe, another chute was installed to clear cinders from the firebox.

Modification

The arrangement was extremely complicated and did not prove to be a success, with the result that in 1915 the two locomotives were reboilered with boilers similar to those used by the standard Class 6, thus converting them to saturated steam locomotives. The piston-valve cylinders were also removed and replaced with smaller 17.5 inches (444.5 mm) bore slide-valve cylinders. In this form they were practically identical to the bar framed Class 6J

South African Class 6J 4-6-0

In 1902 fourteen Class 6 bar framed steam locomotives with a 4-6-0 wheel arrangement were placed in service by the Cape Government Railways. In 1912, when they were assimilated into the South African Railways, they were renumbered and reclassified to Class 6J....

 locomotives that were built by Neilson, Reid and Company in 1902, except that they still had cylinders with a 0.5 inches (12.7 mm) larger bore.

Class 6 sub-classes

When these two locomotives were assimilated into the newly established South African Railways (SAR) in 1912, they were renumbered 659 and 660 and reclassified to Class 6L.

The rest of the CGR’s Class 6 locomotives, together with the Central South African Railways (CSAR) Classes 6-L1 to 6-L3 locomotives that were inherited from the Oranje-Vrijstaat Gouwermentspoorwegen (OVGS) via the Imperial Military Railways (IMR), were grouped into thirteen more sub-classes by the SAR. The 4-6-0 locomotives became SAR Classes 6, 6A to 6H, 6J and 6K, the 2-6-2 locomotives became Class 6Y and the 2-6-4 locomotives became Class 6Z.

Service

The Class 6 family of locomotives were introduced primarily as passenger locomotives, but when the class became displaced by larger and more powerful locomotive classes, it literally became a "Jack-of-all-trades" that proved itself as one of the most useful and successful locomotive classes ever to be designed at the Salt River shops. It went on to see service in all parts of the country except Natal and was used on all types of traffic.

In SAR service the two Class 6L locomotives worked on the Cape main line until they were withdrawn and scrapped in 1934.

See also

• South African Class 6 4-6-0
  South African Class 6 4-6-0
  In 1893 and 1894 the Cape Government Railways placed forty Class 6 4-6-0 steam locomotives in service, twenty-two on its Western System and eighteen on its Midland System. In 1897 ten of them were sold to the Oranje-Vrijstaat Gouwermentspoorwegen. At the end of the Second Boer War in 1901, these...
  
  
• South African Class 6A 4-6-0
  South African Class 6A 4-6-0
  In 1896 and 1897 the Cape Government Railways placed a second batch of fifty Class 6 4-6-0 steam locomotives in service, forty-one on its Western System, six on its Midland System and three on its Eastern System. During the Second Freedom War four were transferred to the Imperial Military Railways...
  
  
• South African Class 6B 4-6-0
  South African Class 6B 4-6-0
  In 1897 and 1898 the Cape Government Railways placed a third batch of fifty-five Class 6 4-6-0 steam locomotives in service, thirty-two on its Western System, twenty-one on its Midland System and two on its Eastern System. During the Second Freedom War seven were transferred to the Imperial...
  
  
• South African Class 6C 4-6-0
  South African Class 6C 4-6-0
  Between 1896 and 1898 the Oranje-Vrijstaat Gouwermentspoorwegen placed twenty-four new Cape Class 6 steam locomotives with a 4-6-0 wheel arrangement in service...
  
  
• South African Class 6D 4-6-0
  South African Class 6D 4-6-0
  In 1898 a fourth batch of thirty-three Class 6 4-6-0 steam locomotives were placed in service by the Cape Government Railways. In 1912, when they were assimilated into the South African Railways, they were renumbered and reclassified to Class 6D....
  
  
• South African Class 6E 4-6-0
  South African Class 6E 4-6-0
  In 1898 the Oranje-Vrijstaat Gouwermentspoorwegen ordered its final six new Cape Class 6 locomotives. When British forces invaded the Orange Free State during the Second Freedom War, these locomotives were taken over by the Imperial Military Railways and after the war they were renumbered into the...
  
  
• South African Class 6F 4-6-0
  South African Class 6F 4-6-0
  In 1900 two redesigned Class 6 4-6-0 steam locomotives were placed in service by the Cape Government Railways. In 1912, when they were assimilated into the South African Railways, they were renumbered and reclassified to Class 6F.-Manufacturers:...
  
  
• South African Class 6G 4-6-0
  South African Class 6G 4-6-0
  In 1901 eight redesigned Class 6 4-6-0 steam locomotives were placed in service by the Cape Government Railways. In 1912, when they were assimilated into the South African Railways, they were renumbered and reclassified to Class 6G.-Manufacturer:...
  
  
• South African Class 6H 4-6-0
  South African Class 6H 4-6-0
  In 1901 twenty-one Class 6 4-6-0 steam locomotives were placed in service by the Cape Government Railways, built to the older Class 6 designs with plate frames...
  
  
• South African Class 6J 4-6-0
  South African Class 6J 4-6-0
  In 1902 fourteen Class 6 bar framed steam locomotives with a 4-6-0 wheel arrangement were placed in service by the Cape Government Railways. In 1912, when they were assimilated into the South African Railways, they were renumbered and reclassified to Class 6J....
  
  
• South African Class 6K 4-6-0
  South African Class 6K 4-6-0
  In 1901 ten American built Class 6 bar framed steam locomotives with a 4-6-0 wheel arrangement were placed in service by the Cape Government Railways. In 1912, when they were assimilated into the South African Railways, they were renumbered and reclassified to Class 6K.-Manufacturer:The Class 6 was...
  
  
• South African Class 6Y 2-6-2
  South African Class 6Y 2-6-2
  In 1903 the Cape Government Railways placed two Class 6 steam locomotives with a 2-6-2 Prairie wheel arrangement in service. In 1912, when they were assimilated into the South African Railways, they were renumbered and reclassified to Class 6Y.-Manufacture:...
  
  
• South African Class 6Z 2-6-4
  South African Class 6Z 2-6-4
  In 1901 the Cape Government Railways placed four Class 6 steam locomotives with a 2-6-2 Prairie wheel arrangement in service, that were soon modified to a 2-6-4 Adriatic wheel arrangement. In 1902 another four locomotives were placed in service, built with the 2-6-4 wheel arrangement. These latter...
  
  
• Tender locomotive numbering and classification
• The 4-6-0 "Ten-wheeler"
• List of South African locomotive classes