In the US I would take a sleeper train from Seattle to Chicago instead of a plane provided the sleeper train runs 180 mph on average. That would put me in Chicago in about 10-12 hours, meaning I could get to Union Station in Seattle, get on the train, sleep a full night, wake up, eat breakfast, and disembark in Chicago. The red-eye to Chicago, which is a comparable trip, really sucks because you only get about 3 hour…
"airfare-level prices"? In Germany and Austria my experience was that flying was generally cheaper than the train, and sleeper trains more expensive still. I'm on a (day) train between Berlin and Vienna this very minute and it costed me €99 (one way!) where as a flight would have been about €50. You can get cheaper tickets if booking well in advance (months) but the same applies to budget airlines.
To be fair to travel betwee Berlin and Vienna City centres you'd need to add at least a €10 in each end for ground transport.