During winters in the state of Alaska and Pacific northwest, the cost of operations rose significantly due to additional expenditure on airplane de-icing, frequent flight cancellations and accommodation costs of displaced passengers.

FORBES: Alaska's Earnings Will Get A Tailwind From Higher Capacity & Passenger Traffic

Most services offer a mixture of sleeper compartments with room for two or four passengers, six-person dormitory-style couchettes and seat accommodation.

BBC: Europe's eight best night trains