railhead vs depot

railhead and depot both are nouns.

Word	Noun	Adjective	Verb	Adverb
railhead	Yes	No	No	No
depot	Yes	No	No	No

As nouns, depot is a hypernym of railhead; that is, depot is a word with a broader meaning than railhead:

railhead: a railroad depot in a theater of operations where military supplies are unloaded for distribution
depot: a depository for goods

Other hypernyms of railhead include entrepot, storage, store, storehouse.

railhead (noun)	depot (noun)
a railroad depot in a theater of operations where military supplies are unloaded for distribution	station where transport vehicles load or unload passengers or goods
the end of the completed track on an unfinished railway	a depository for goods