train station vs railroad station

train station and railroad station both are nouns.

Word	Noun	Adjective	Verb	Adverb
train station	Yes	No	No	No
railroad station	Yes	No	No	No

As nouns, train station and railroad station are synonyms defined as:

train station and railroad station: a terminal/node where trains load or unload passengers or goods

Other synonyms of train station include railroad terminal, railway station, train depot.

train station (noun)	railroad station (noun)
a terminal/node where trains load or unload passengers or goods	a terminal/node where trains load or unload passengers or goods