With LEO constellations coming online rapidly, I think it's time the railroads start competing for pax travel again. Start at the high end. My dad worked for BN and I remember the corporate business car: walnut paneling, frosted glass, brass, comfortable seats. I would totally take that: package up the cost of hotel, half the airfare, and meals, and have your offsite, workshop, or other in-person event on the train.
If you put 10 passengers in one fancy business railcar, it will cost 50c/km and reduce greenhouse emissions relative to flying by half rather than by a factor of ten.
Night/hotel trains only make sense with decent density.
