overhead railway vs elevated railway

overhead railway and elevated railway both are nouns.

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

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

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

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

overhead railway (noun)	elevated 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