It depends hugely on when you book--both time in advance and time of year--as well as any sales going on. Which can vary a TON in Europe as well. I almost always take trains within Europe but they're no bargain.

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saalweachter 4 hours ago | parent [-]

Re: when you book, for the East Coast trains time of day matters greatly.

If you book a train from NYC to Philadelphia on Dec 9, there are four trains leaving before 6am with coach tickets for $10.

NYC to Boston has similar early morning prices.

	▲	ghaff 4 hours ago \| parent [-]
		Right. I'm not going to NYC for now but I saw the end-of-year sale in my inbox recently. Pricing varies a lot. (And I usually don't book Acela on my own dime absent a bargain; the transit time isn't much different from the regional.)