railroader vs railroad man

railroader and railroad man both are nouns.

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

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

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

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