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(January 2008)| A switcher or shunter (Great Britain: shunter;
Australia: shunter or yard pilot; USA: switcher or switch
engine, except Pennsylvania Railroad: shifter) is a small
railroad locomotive intended not for moving trains over long
distances but rather for assembling trains ready for a road
locomotive to take over, disassembling a train that has been
brought in, and generally moving railroad cars around – a
process usually known as switching (UK: shunting). They do this
in classification yards (Great Britain: marshalling yards).
Switchers may also make short transfer runs and even be the only
motive power on branch lines and switching and terminal
railroads. The term can also be used to describe the workers
operating these engines or engaged in directing shunting
operations. The typical switcher is optimised for its job, being
relatively low-powered but with a high starting tractive effort
for getting heavy cars rolling quickly. Switchers are