In 1914 the South African Railways placed fifteen Class MC1 Mallet articulated compound steam locomotives

Compound locomotive

A compound engine unit is a type of steam engine where steam is expanded in two or more stages.A typical arrangement for a compound engine is that the steam is first expanded in a high-pressure cylinder, then having given up heat and losing pressure, it exhausts directly into one or more larger...

 with a 2-6-6-0

2-6-6-0

In Whyte notation for the classification of steam locomotives by wheel arrangement, a 2-6-6-0 is a locomotive with one pair of unpowered leading wheels, followed by two sets of three pairs of powered driving wheels, and no trailing wheels...

 wheel arrangement in service.

Manufacturer

Orders for an improved version of the Class MC

South African Class MC 2-6-6-0

In 1912 the South African Railways placed ten Class MC Mallet articulated compound steam locomotives with a 2-6-6-0 wheel arrangement in service.-Manufacturer:...

 were placed with 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) in 1913. When the fifteen locomotives were delivered and placed in service in 1914, they were classified as Class MC1 and numbered 1634 to 1648.

Characteristics

The improvements in the Class MC1 consisted mainly of a redesigned boiler that included a superheater, instead of the saturated steam boiler of the Class MC, and 0.5 inches (12.7 mm) larger diameter low pressure and high pressure cylinders. The result was a much better performing locomotive with an increased tractive effort brought about by the larger cylinders.

In a compound locomotive steam is expanded in phases. After being expanded in a high pressure cylinder and having then lost pressure and given up part of its heat, it is exhausted into a larger volume low pressure cylinder for secondary expansion, after which it is exhausted through the smokebox.

In the compound Mallet locomotive

Mallet locomotive

The Mallet Locomotive is a type of articulated locomotive, invented by a Swiss engineer named Anatole Mallet ....

, the rear set of coupled wheels are driven by the smaller high pressure cylinders which are fed steam from the steam dome. Their spent steam is then fed to the larger low pressure cylinders that drive the front set of coupled wheels. By comparison, in the more usual arrangement of simple expansion, steam is expanded just once in any one cylinder before being exhausted through the smokebox.

Service

The Class MC1 was placed in service on the coal line from Witbank to Germiston. In later years some also saw service on the Natal main line and the Cape Midlands System, while a number of them were transferred to the Cape Western System where they served as banking locomotives up the Hex River Pass between De Doorns and Touws River. They remained there until they were withdrawn from service by 1939.

Gallery

See also

• Mallet locomotive
  Mallet locomotive
  The Mallet Locomotive is a type of articulated locomotive, invented by a Swiss engineer named Anatole Mallet ....
  
  
• South African Class MA 2-6-6-0
  South African Class MA 2-6-6-0
  In 1909 the Natal Government Railways placed a single 2-6-6-0 Mallet articulated compound steam locomotive in service. In 1912, when it was assimilated into the South African Railways, it was renumbered and classified as Class MA.-Manufacturer:...
  
  
• South African Class MB 2-6-6-0
  South African Class MB 2-6-6-0
  In 1910 the Natal Government Railways placed five 2-6-6-0 Mallet articulated compound steam locomotives in service. In 1912, when they were assimilated into the South African Railways, they were renumbered and classified as Class MB.-Manufacturer:...
  
  
• South African Class MC 2-6-6-0
  South African Class MC 2-6-6-0
  In 1912 the South African Railways placed ten Class MC Mallet articulated compound steam locomotives with a 2-6-6-0 wheel arrangement in service.-Manufacturer:...
  
  
• South African Class MD 2-6-6-2
  South African Class MD 2-6-6-2
  In March 1910 the Central South African Railways placed a single experimental Mallet articulated compound steam locomotive with a 2-6-6-2 wheel arrangement in service...
  
  
• South African Class ME 2-6-6-2
  South African Class ME 2-6-6-2
  In January 1912 the South African Railways placed a single Class ME Mallet articulated steam locomotive with a 2-6-6-2 wheel arrangement in service.-Manufacturer:...
  
  
• South African Class MF 2-6-6-2
  South African Class MF 2-6-6-2
  In 1911 the Central South African Railways placed nine Mallet articulated compound steam locomotives with a 2-6-6-2 wheel arrangement in service. In 1912, when they were assimilated into the South African Railways, they were renumbered and classified as Class MF...
  
  
• South African Class MG 2-6-6-2
  South African Class MG 2-6-6-2
  In 1911 the Central South African Railways placed a single experimental Mallet articulated compound steam locomotive with a 2-6-6-2 wheel arrangement in service...
  
  
• South African Class MH 2-6-6-2
  South African Class MH 2-6-6-2
  In 1915 the South African Railways placed five Class MH Mallet articulated compound steam locomotives with a 2-6-6-2 wheel arrangement in service.-Manufacturer:...
  
  
• South African Class MJ 2-6-6-0
  South African Class MJ 2-6-6-0
  Between 1914 and 1921 the South African Railways placed eighteen Class MJ Mallet articulated compound steam locomotives with a 2-6-6-0 wheel arrangement in branch line service.-Manufacturers:...
  
  
• South African Class MJ1 2-6-6-0
  South African Class MJ1 2-6-6-0
  In 1918 the South African Railways placed eight Class MJ1 Mallet articulated compound steam locomotives with a 2-6-6-0 wheel arrangement in branch line service.-Manufacturer:...
  
  
• Articulated locomotive numbering and classification
• The 2-6-6-0 Mallet
• List of South African locomotive classes