I too have had the same problem with the Hub. I had rail, elevated rail and HSR running through it and yet nothing happens even though there is incredible traffic on my rail and elevated rail/subway. When I removed the Hub and put a rail and elevated rail station in the same spot they both worked fine.
I made the point of uninstalling and reinstalling the game with the latest NAM and updates and the problem still exists. Any help would be greatly appreciated.
Thanks.