I created a screencast showing how I made the Airbus A400M model. I plan on adding one for the Piaggio Avanti II as well. The screencast can be found here:

http://www.youtube.com/user/propdesignsupport

It's about 15 minute long and there is no sound. In this case I scaled the ter by 2.5 and rebuilt the ter and the rails. This prevented downstream errors that would occur. Scaling the ter alone did not fix the problem. The rebuild was necessary.