Is that G scale?
Whatever it is, it's really friggin cool.
I wonder if he created the interface for the Android phone?
Definetly something I want to try with my Raspberry Pi.
I think the R-Pi is still a little to big for most o scale engines. It could definitely fit in the tender of a large steam engine but might be kinda tight inside a dual motored diesel.
The great thing about the R-Pi is that also has sound outputs and you can attach a video camera to it too.
There was a recent thread on the electrical forum inquiring about model RR projects using an Arduino or Raspberry Pi.
Lots of info across the Internet about R-Pi projects.