Very nice, and very realistic! I'm wondering if it could do with subtle signs of wear here and there, just to up that realism even further (unless it's deliberately pristine, in which case ignore me!).
I think it looks quite good and realistic. The lighting is something that could be improved imo, it's a bit flat. I'd try to recreate the picture more, there's a nice contrast between very warm and very cold lighting in it. Other that that, those coloured signs look very artificial for some reason.
Looking nice! really like what you have here. Good variation in materials and nice lighting. I agree with Wesley, it's looking like no-one has set foot in that subway. I would suggest adding grime, scrapes, cracks, worn paintwork, even slight rubbish that's been left on the floor would help a lot to make it more realistic.…