From Longman Dictionary of Contemporary Englishcouchettecou‧chette /kuːˈʃet/ noun [countable] British English TTTa narrow bed that folds down from the wall in a train, or a comfortable seat on a night train or boat → sleeping car
Examples from the Corpus
couchette• It is a moment before the long hours in cramped quarters, which makes up spending a night in a couchette.• She sat on the opposite couchette and picked up the paperback he had been reading.• Graham tossed the paperback on to the opposite couchette and made his way to the dining car.Origin couchette (1900-2000) French “small bed” 