High-temperature superconductors are generally considered to be those that demonstrate superconductivity at or above the temperature of liquid nitrogen, or −196 °C (77 K), since this is the most easily attainable cryogenic temperature.

If you need to cool the track with liquid nitrogen, I'm afraid it's not a practical technology. this side of the asteroid belt.

Those whom the Gods wish to destroy They first make mad. -- Euripides