It is done! Trainz is now arriving to an iPad at the App Store on December 4th. You will be able to build a layout and drive trains on the iPad while sitting on a couch.
To the fat guy in the red suit, could you send an iPad my way?
Developing a route without a mouse might seems tough but as the following video shows, using your finger and other controls it looks just the same.
Route Creation in Ipad: