[andrewflnr]

Thanks. I'm not sure I understand the part about "quantum flux tubes". I take it that they're leaks through flaws in the superconductor (which should exclude the field entirely). Is the superconductor is being gripped or pinned by these lines of force running through it, like a piece of cheese on a toothpick? But that doesn't quite explain how it can move along a field.

[JangoSteve]

I think the magnets on the track piece may be arranged NSN like this:

  NNNNNNNNNN
  SSSSSSSSSS  ==>
  NNNNNNNNNN

Which allows movement as indicated. In the part of the video where it's just locked stationary above a square magnet, it appears maybe the magnet as this arrangment:

  NNN      NS
  NSN  or  SN
  NNN

Which locks it entirely in-place, not allowing movement. And then in the part where it's spinning, I think maybe the magnet is S on the inside and N on the outside or something:

      NN
     NSSN
    NS  SN
     NSSN
      NN

Allowing it to spin. But this is speculation based on my limited understanding (but I noticed no one else was answering, so I thought I'd give a shot).