A good question on the track radius. I would tend to believe that 0-72 would be for scale wheels (and likely fixed pilot) version. If that version has a fixed pilot, then I can see o-72 due to the long wheel base.
There's a video of a hi-rail version below. At the 4:50 mark you can see the unit up close, and it is navigating turns much sharper than 0-72. (And the pilot clearly is not fixed.)
