I've spent 140 hours on overnight trains and 14 nights on cruises. One is more comfortable, and the other is more fulfilling.
Cruises are more relaxing, with a bigger list of amenities and larger cabins, but I'd rather book an overnight train for a more unique vacation.
https://www.businessinsider.com/overnight-train-travel-vs-cruises-why-i-prefer-rail-journeys