A sleeper car refers to a type of specially designed train or car that has comfortable beds or sleeping arrangements for passengers to rest or sleep during long journeys. Full definition
The best sleeper cars ever built are quick, a blast to drive, and low - key to all but the best - trained enthusiast eyes. (digitaltrends.com)
Some command extra fees (for overnight sleeper cars, for example), and others don't. (theprofessionalhobo.com)
The passenger trains usually consist of five passenger cars and a dining car, the night service has an additional two sleeper cars added to this. (greatrail.com)