railroad man vs railwayman

railroad man and railwayman both are nouns.

Word	Noun	Adjective	Verb	Adverb
railroad man	Yes	No	No	No
railwayman	Yes	No	No	No

As nouns, railroad man and railwayman are synonyms defined as:

Other synonyms of railroad man include railroader, railway man, trainman.

railroad man (noun)	railwayman (noun)
an employee of a railroad	an employee of a railroad