5G50.50 Superconducting Train


Induction, superconductivity, magnetic fields from currents


A pair of superconducting slugs embedded in a styrofoam train will float above a magnetic track when the slugs are cooled to the boiling point of liquid nitrogen. The train moves around the track with only air friction slowing it down.



  • [1] Superconducting train
  • [1] Magnetic track
  • [1] Small dewar of liquid nitrogen
  • [1] Styrofoam cup
  • [1] Aluminum plate
  • [1] Sheet of paper

Safety Equipment

  • [1] Safety goggles
  • [2] Safety glove

Classroom Assembly

  1. Place the track somewhere visible and away from ferromagnetic objects.
  2. Put the aluminum plate on the magnetic track.
  3. Put the superconducting train on top of the plate.

Important Notes

  • Liquid nitrogen can cause frostbite, blindness, and asphixiation. Handle with care in well-ventilated areas.
  • Cooling the train at a slightly elevated position is essential.
  • These magnets may demagnetize credit cards.
  • The heavy barium metal in the superconductor likely makes it poisonous. Wash your hands afterwards.


  1. Put on your safety goggles and gloves.
  2. Pour some liquid nitrogen from the dewar to the cup.
  3. Use the styrofoam cup to cool the superconductors with liquid nitrogen until rapid boiling in the train stops.
  4. Top up the liquid nitrogen level in the train.
  5. Give the train a gentle tap to make it go around the track.
  6. Remove the aluminum plate.
  7. Place a sheet of paper underneath the train to show it is floating on the track.


Additional Resources


  • PIRA 5G50.50


  • Don't attempt this at home!

Last revised

  • 2018


  • The superconducting material is probably an yttrium barium copper oxide, or YBCO.

Related AV

Related demos

  • Eddy current tubes
  • Eddy current ramps


If you have any questions about the demos or notes you would like to add to this page, contact Ricky Chu at ricky_chu AT sfu DOT ca.