I literally rode amtrak into DC from Boston during a lull in storms back in early 2011. Did it because my USAir flights had been cancelled 3 times. Was lucky because Amtrak wasn't steadily operating and I had one of the few that went through. I think another time I went up to Boston on an overnight and it snowed enough that the automatic doors were jammed a bit open. IOW, I've been on those trains for 10-13 hours when the weather really stunk.
I'll just continue to say that, if a train can't get through, then it's pretty doubtful that it's going to be safe to drive. Most of the time, trains are plenty comfortable. You can move around, there's food (until things run out), less stress. I've white knuckled cars in snowy conditions, and it is not fun.
DC to Boston is the key point there. The rail network in the northeast is lightyears better than south of DC.
