We don't have synonyms for garratt yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are garrett, jarratt and barratt.
(n) :
A steam locomotive that is articulated in three parts, with a boiler mounted on the centre frame, and two steam engines mounted on separate frames, one on each end of the boiler.
(n) :
A steam locomotive that is articulated in three parts, with a boiler mounted on the centre frame, and two steam engines mounted on separate frames, one on each end of the boiler.