It's no less silly here it would be elsewhere. A conventional TGV - or better, a Northern extension to the Channel Tunnel line - makes a lot more sense.
Meanwhile New Scientist has been reporting the imminent arrival of room temperature superconductors for a while - but obviously they're still not here yet.
But (as usual), this is out of reach because of cost, which is to say the cost of things, which is to say, in large measure, the cost of making things. We're still very bad at that.
(Gee, I could repeat this in so many contexts...) Words and ideas I offer here may be used freely and without attribution.