* Common nouns refer to general, non-specific things. They are not capitalized unless they start a sentence.
* Proper nouns refer to specific people, places, or things and are capitalized.
"Tracks" can refer to many things:
* Footprints: The animal left tracks in the mud.
* Railway lines: The train sped along the tracks.
* Musical recordings: They released their latest album with 10 tracks.
Since "tracks" refers to a general concept that can be applied to many different things, it is a common noun.