Here's a question--what do you do with your luggage in NYC after checkout time at the hotel, but before you have to leave (in this case late afternoon train tickets)? I sure don't want to sit in Penn Station for hours! I don't think there are any public lockers availabe in NYC any more...what have you done with your bags?
(Our hotel will let us store our bags there before check in time, but not sure they'll want to watch them after we check out!)

Your hotel will certainly keep your bags after check out. Some hotels charge for this, but most don't. I think I also read here that Amtrak may now have luggage storage.

I think Amtrak still has baggage storage, but you have to have an Amtrak ticket.

Another possibility--Macy's is quite near Penn Station. They used to have a coat and parcel check on the mezzanine. Perhaps you could leave your bags there.

I assume your hotel will let you leave your bags, but depending on hotle location.

As Mclaurie said, most hotels will keep your luggage even after checking out. Service is usually free, but they do expect a tip ($1 per bag).

thanks all--I'll ask at the hotel, and check with Amtrak (we do have Amtrak tickets).

Amtrak does hold bags, they do charge per bag, if I remember it is about 4$ per bag. When you pick them up, get there at least 1/2 hour before your train departs in case there is a line at baggage.