well i guarennte u there's a way to keep a super cold energy field around that thing or just the object itself with vibrational frequency more then 1 way to do anything!
probably similar to some of the protypes they used 2 build the underground bases networks all over earth or perhaps past cilvizations and other interstellar socities...
yea theres some et societs in our solar system and other star systems with those.....
theres even interdimesnional trains that can jump threw portals to rail systems in other dimensions
you can have a train shift between running on a rail system and being a spaceship to amasing stuff our imagination!