commuter train vs commuter

commuter train and commuter both are nouns.

Word	Noun	Adjective	Verb	Adverb
commuter train	Yes	No	No	No
commuter	Yes	No	No	No

As nouns, commuter train and commuter are synonyms defined as:

commuter train and commuter: a passenger train that is ridden primarily by passengers who travel regularly from one place to another

commuter train (noun)	commuter (noun)
a passenger train that is ridden primarily by passengers who travel regularly from one place to another	a passenger train that is ridden primarily by passengers who travel regularly from one place to another
	someone who travels regularly from home in a suburb to work in a city