This weekend I mapped a spot in downtown Greensboro where the railroad tracks cross Elm. The connection was spotty and I was stationary, so I do not know how far it extends.
Sitting in an office tower in downtown Greensboro - 4G just lit up briefly. I was trying to connect to the web and got "no mobile data" and no icon, then 4G with 3mb up, then back to 3G. Encouraging!