Now this is what I’m talking about. Developers Daniel Wagner, Thomas Pintaric, Florian Ledermann, and Dieter Schmalstieg of Vienna University of Technology created this project in which a 3D train is displayed on an HP Ipaq. The track exists in “real life” (aka. RL) and the train is augmented. The site contains lots of movies and a PDF explaining the approach.
Photo credit: Vienna University of Technology