Merging tracks
When you import tracks into TrailRunner, some parts of the tracks might overlap and other parts will describe new courses. To eliminate duplicate tracks and way-points TrailRunner can merge these.
Added to that, GPS receivers sometimes get lost and record locations that are way off your real track. If that happens, you need to manually correct the tracks path.
Removing overlapping parts of tracks
For a good explanation, please check out the Maintain your local network of tracks section of the QuickGuide tutorial http://trailrunnerx.com/en_tutorial.
Manually correcting a path
Sometimes you need to manually relocate a way-point or track-points on a track. (A track is nothing more than a line through a sequence of track-points). To drag way-points or track-points around, you need to ⌘-click onto the way-point or track, keep the ⌘-key down and then drag the element to the target location.