Plarail TOMY Thomas NEW RELEASES

I can guess that's because most people use blue track, and if it had been all grey, it would have appealed to only grey track users, and be considered a specialty set... But with it mixed, grey track users will still want it, and maybe more blue track users might be inclined to mix it up too?

That makes sense! I’ve always gotten the impression that the blue track is important to Japanese Plarail fans for aesthetic and nostalgic reasons and Tomy alters that at their peril! An all gray set might appeal to a certain segment of collectors but at the risk of alienating a wider audience.