Works for me
I emailed a GPX file from the motion X GPS. I tapped on that and then selected open in application then selected this app. I was able to drag the end of the track to where I wanted it and then I exported it back to my GPS Hiking application. Sometimes I forget to stop the app until Im in my car and several miles away so this app I use for trimming the end of the track which it does it very well Im using the iPhone 7+ with iOS 10.1.1. I just had to change the map in the settings and I think I chose the topographic map.
DudemanLA about
Track Editor, v1.4