I KNEW, i just knew Kei would make a badass entrance with her badass ice bike stand, she even managed to freeze Josuke's bubbles which then managed to hit Tooru somehow, I'm guessing something like the frozen bubbles being a perfect sphere just like the steel balls, that have spin stored inside...
If Crazy Train really is the name of the calamity stand then it would mean... Part 8 Crazy Diamond is the villain's stand, paralleling Part 8 Killer Queen being (part of) the hero's stand...