Use the Station and Offset View and add the Linework that you want to Flatten. This works with Alignments, Linework, Polygons, text but doesn't support everything in TBC (like Mass Haul, Cut Fill Maps, Surface Color Maps etc.) but it does what you are asking. You can exaggerate the Vertical like you can a profile or Section or 3D view using CTRL SHIFT WHEEL etc.
You create the view against a selected alignment and then use add / remove Members from Station / Offset View and it recomputes them to Station and Offset and draws them in the view. You can exaggerate the view as you need.
Alan