railyard vs tract

railyard and tract both are nouns.

Word	Noun	Adjective	Verb	Adverb
railyard	Yes	No	No	No
tract	Yes	No	No	No

As nouns, tract is a hypernym of railyard; that is, tract is a word with a broader meaning than railyard:

railyard: an area having a network of railway tracks and sidings for storage and maintenance of cars and engines
tract: an extended area of land

Other hypernyms of railyard include parcel, parcel of land, piece of ground, piece of land.

railyard (noun)	tract (noun)
an area having a network of railway tracks and sidings for storage and maintenance of cars and engines	a bundle of myelinated nerve fibers following a path through the brain
	a system of body parts that together serve some particular purpose
	a brief treatise on a subject of interest; published in the form of a booklet
	an extended area of land