Superelevation is described and spec'd by the NMRA and should be an option in XtrkCad.
Maybe like the elevation feature, you let it determine the max elevation and then calculate it at intervals from the highest point outward to the end of it in the easement area.
Afterward you could just go to the superelevation mode and see what that height in decimal inches as well as mm, at any given point.
Steve
This would require the addition of cant (tilt) to all track objects as well as elevation. Quite complicated if it includes connection between tracks that are canted (or not) as well.