elevated railway vs overhead railway

elevated railway and overhead railway both are nouns.

Word	Noun	Adjective	Verb	Adverb
elevated railway	Yes	No	No	No
overhead railway	Yes	No	No	No

As nouns, elevated railway and overhead railway are synonyms defined as:

elevated railway and overhead railway: a railway that is powered by electricity and that runs on a track that is raised above the street level

Other synonyms of elevated railway include el, elevated, elevated railroad.

elevated railway (noun)	overhead railway (noun)
a railway that is powered by electricity and that runs on a track that is raised above the street level	a railway that is powered by electricity and that runs on a track that is raised above the street level