Oh wow! This looks absolutely awesome. I'd love to take a trip on some old railroads. The only thing is... what if they get to a section where the rails have been ripped up or something?
It looks like it has rubber wheels held onto the track with retractable steel guide wheels like most railroad maintenance vehicles in use today. I'm guessing they just pull up the steel guide wheels and drive normally.
From the article: "The SEFT-1 can drive on roads like an ordinary car, or use its extra set of front wheels to guide it along the rails."