slip coach vs slip carriage

slip coach and slip carriage both are nouns.

Word	Noun	Adjective	Verb	Adverb
slip coach	Yes	No	No	No
slip carriage	Yes	No	No	No

As nouns, slip coach and slip carriage are synonyms defined as:

slip coach and slip carriage: a railway car at the end of the train; it can be detached without stopping the train

slip coach (noun)	slip carriage (noun)
a railway car at the end of the train; it can be detached without stopping the train	a railway car at the end of the train; it can be detached without stopping the train