I just got Sprint LTE service for the first time on my iPhone in New York City. I was riding the 1 train and at the above ground station at 125th St, and I noticed I got LTE service! What a feeling!
I did a quick speed test and I got 38 ms ping, 19.27 mbps down, and 8.65 mbps up. The train was moving and heading back under ground, so I have no idea actually what kind of signal strength I had.
Good luck everyone with the Hurricane! Stay safe!