TrailRunner

I must admit that the United States Geological Survey (USGS) is more and more getting my best friend. The scientific agency of the United States government offers many web-based services providing geographical data of the United States and partly about the rest of the world.
The newest discovery is the elevation database. Thanks to the pointer from Mike Jacobsen, TrailRunner now can query the online-database for every single point in your TrailRunner document and will receive the corresponding elevation. Best of all: It seems to cover the whole planet.
To download elevation data for you net of tracks you need a calibrated document. The menu command File > Import > Elevation data from Internet-Service will start the download. As it takes long, you might also check out the same locations in the fresh air, while the download is proceeding.