Burning a track is sort of like a higher-order exhaustion.
Imagine how most days you use your phone and it runs out of juice. Charging it overnight means it's back in use -- this is marking a track, it's easily cleared.
Now, if you were some kind of computer whiz, maybe you'd overclock your phone to hack past some high-security defences, but that overheats and damages a part of the phone. That part can't just be fixed with a charge overnight, you have to get it repaired at a specialty shop -- this is burning a track, you need extra effort to clear it.
Hope that's clearer!