I picked up Model Railroad Planning 2007 at my bookstore today and it has a long article in which a model railroader made his railroad in Trainz first to check it out. Test-running your model railroad in cyberspace is a great article with some really nice screen shots. He did a nice job on the virtual version.
It's a publication from Model Railroader Magazine and can be ordered on the web here:
https://secure.kalmbach.com/AdvantageWeb/eCirc/Offer.aspx?PromotionCode=IF6CMP1
Way cool Ed, and Happy New Year!
I'll go over to the Trains forums and give a pitch on the virtues of Virtual Modelling.

John