A "trackie" can be described as individual who is completely obsessed with track and/or cross country. A trackie knows anything and everything about running. You can see a trackie talking to every runner in the area and knowing everything about their running history. A trackie is also condsidered a track/cross country nerd.
"Oh, that girl that is seeded first runs a 4:40.35 1500. She's my idol."
"You know everything about everyone you trackie."
A track star is commonly referred to as a really good runner. Mostly in the distance events. If you run anywhere from the mile and up and are condsidered top in your school, you are a "track star".
"What more could you ask for in a girl; she's hot AND a track star!"