Turns out I was wrong. These applications use niobium-titanium or niobium-tin, both of which are type II superconductors. They do have relatively low Tc -- 10-2

Turns out I was wrong. These applications use niobium-titanium or niobium-tin, both of which are type II superconductors. They do have relatively low Tc -- 10-20 kelvins versus >80 kelvin for the best HTSC, and are cooled even lower to maximize the critical field and current (i.e. maximum they can withstand before losing superconductivity).