GPSFunRunner 3D is a third party application which allows the comparison of two separate .tcx files within three dimensions
The Full Version will allow for comparison of more than 10 minutes of data (exceeding roughly 1.5 miles) and allow for speed or heart rate (bpm) to be used as thresholds for the pace mode.
The Full Version is due for release in the Autumn of 2017.
3D text stating Gap Leader and Gap Loser will indicate where on the training route the maximum gap was detected.
Interval training - results comparison from 2 attempts at the same route 2 days apart: