railway yard vs tract

railway yard and tract both are nouns.

Word	Noun	Adjective	Verb	Adverb
railway yard	Yes	No	No	No
tract	Yes	No	No	No

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

railway yard: 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 railway yard include parcel, parcel of land, piece of ground, piece of land.

railway yard (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