Another thing nobody ever considers is making the modifications and/or upgrades to standard freight lines to be able to throw some passenger cars on them for standby rides. You’d have to be pretty hard on the on-off scheduling, but it seems there’s a buck and some easy transport to be made there as long as the regulators and lawyers aren’t allowed to finger into it...
My understanding is that the freight railroads are very reluctant to rent track time to passenger trains. I’m sure there are also regulatory/liability issues involved, but the freight lines seem to be primarily concerned (maybe rightly so) with the potential disruption to their schedules of having to share track with passenger trains, at least in the southeast where I live.