Track in the context of finding or knowing where something is means. To be able to always know where it is to be able to follow it/them by either mechanical or digital electronic means or by following signs that have been left, by the machine/animal/person/ alien visitor etc/ Trace is similar but involves searching for clues as to where something/somebody was last seen or known to be or reported to be. Mail is tracked by bar code scanners across the world. Cars and vehicles can be tracked by navigation equipment "GPS" OR "SAT NAV" <- UK word for GPS. People can be tracked by other people but not in real time by finding clues broken branches squashed undergrowth foot prints etc. Cars can be tracked by following tire/tyre prints. "tire American Tyre UK" Things and people can be traced by following clues and asking questions "did they go to their place of work at what time, did they arrive home later as expected. Where was the last reported sighting." To trace means to draw something by following an outline left behind. "tracing paper" does this it is transparent paper you can see through it and copy the outline of what's underneath to produce a copy.

the difference is that: track is a road or a path that is not built but made after a lot of walking. trace is any mark or sign that indicates that someone or something was where the trace is for example a piece of clothing.