This project was created by Antipodes and presented at the 2013 Bay Area Maker Faire. Rather than using a typical rail system, this MagLev train uses magnets alternating polarity to move it along the tracks. XBee radios allow for the train to be controlled remotely.
Detailed documentation can be found on the project page here.
And, in the video below, you can watch the train in use and get a walkthrough of all components involved.