Any locomotive featuring two or engines (i.e. cylinders, rods, and wheels) under one boiler, mounted on separate or hinged frames. Permits large locomotives to snake around curves more easily.
A locomotive which is made up of several units, with each unit being pivoted to the next unit. Each unit is on a separate frame which is free to swivel relative to the frame of the next unit.
A locomotive where two engines (sets of cylinders, valve gear and wheels) were provided under the same frame but pivoted to allow transition through curves in spite of the long wheelbase. Garratt and Mallet were two types of articulated locomotives. Much favoured in Africa, India and the US but not common in Europe and the UK. Some locomotives built to Fairlie's patent also had two engines but not all were articulated.
a steam lovomotive the driving wheels of which are in distinct sets, one or more of which are hinged or pivoted. Fairlie, Beyer-Garrett and Mallet are the major types.
Articulated locomotive usually means a steam locomotive with one or more engine units which can move relative to the main frame. This is done to allow a longer locomotive to negotiate tighter curves. Articulated locomotives are generally used either on lines with extreme curvature—logging, industrial, or mountainous railways, for example—or for very large locomotives to run on railways with more standard track curvature.