From en.wiktionary.org:
** English
*** Noun
[en-noun]
1. [en] A small locomotive used for shunt ing wagon s, etc.
2. [en] [en] A small gasoline engine serving as an auxiliary to a diesel engine (mainly in older designs from the 1930s to 1950s), providing heat to warm it up and, when engaged with a clutch, providing cranking to start it up.
**** Related terms
{{col|en |donkey engine }}