If one could get 116V/230V between the rails, get it through the wheels into a PSU with some large caps to aid it a little when the tracks are uneven.
Add Wireless HDMI, mouse/keyboard and Wifi. See where I am going with this?

You could have the train "choo choo" around your room while you use it, and as added effect given that this is XtremeSystems the train will speed up when the computational load increases. A function of this will be increased airflow which improves cooling as well.

Optional, but highly recommended. Put a toy Delorean at it's front, just hope you don't overclock so much that your train hits 88Mph!