Mushroom_2, the a/c I fly (733 and 737) don't have any facility to fly a track. If ATC asked me to 'maintain my track' I'd have to continuously use the autopilot Heading mode to keep the trackline where it was.
This is probably just about as safe as flying on magnetic headings for separation, because one moment of distraction and we've drifted off our track into someone else....