I can follow your enthousiasm about fuji velvia, at least I shared it at the start. When using it more often for landscape, where it’s more or less invented for, I saw more and more disadvantages. It approaches kitsch sometimes in oversaturated greens. I can’t see however, if you love it, why it would not be appropriate for subways. It does not, in my experience, handle fluorescent light any worse than other slide films. And if you scan you can correct the cast, or you can use a magenta correction filter. Flash would be better for that matter but would have too many other disadvantages for me personally. It is already a quite contrast film, with flash it doesn’t get softer