The original Hyperloop system was supposed to be powered by linear induction motors spaced along the track. The pod doesn't have propulsion capability, except maybe an emergency system. So the pod/track interface is pretty much set by the propulsion system.

For trains, linear induction motors have usually been paired with magnetic levitation, as in the Transrapid system. But they don't have to be. Many roller coasters with a linear induction motor launch system have been built; Flight of Fear at King's Dominion, by Premiere Rides, was the first, in 1996. For a 1-mile test track, outsourcing the whole job to Premiere Rides or Intamin would be a good move. Intamin, which mostly makes amusement park rides, also has a transportation division. They build monorail systems. Intamin would just have to combine the car design from their P8 monorail[1] with their linear induction motor launch system.[2] By Intamin standards, a fast 1 mile loop with no hills is easy. ("We can put in a vertical loop for a small extra charge...")

[1] http://www.intaminworldwide.com/transportation/Home/news/Sha... [2] http://www.intaminworldwide.com/amusement/RollerCoasters/LSM...