I was standing at 34th street around 3 o'clock when the announcement came that it was cancelled -- a surprisingly clear and understandable announcement, by NYC standards. I guess they had the train standing at 2nd avenue for anyone who wanted to walk through it, but they didn't post that information until I had given up on the whole thing. Oh well ... these things happen.
It is always a nightmare when something like this happens during your travels, but in NYC, problems seem to multiply. Information at Penn Station was spotty. At first there was an announcement about taking a bus to Secaucus, which doesn't make sense to me, since the train I eventually took from Hoboken would not have stopped there. I was able to figure out how to get to Hoboken because I know the rail network, but not having any Dover trains on the display screen when we got there was confusing. If I didn't know the layout of the place, I might still be standing there in that small gaggle waiting for a track assignment (OK, I wouldn't still be there now, but you get my drift).
You are absolutely right about a powered-up cell phone, but mine was nearly dry because I'd been using it all day with no place to plug in. I guess a younger person might know how to get around that.