Hi Paul,
Teporrary terrain would require a lot of additional work when you have like 30 alignments and change vertical alignments a lot. That was a reason why it wouldn't work for me. However when you suggested this I considered the idea again... and created dummy corridors with templates that can create temporary terrains for all alignments with a single mouse-click. Then I display gridded-models of terrains or simply the corridor components (just to avoid drapoing text on triangles). Now the stenicl method is efficient enough for me.
Thanks for this little brain-storm!
Regards,
Adam