noun
sleeping-car ticket; berth ticket
A ticket specifically for a sleeping berth on a train, often used in the context of overnight train travel in Japan.
寝台券を買って、夜行列車に乗った。
I bought a sleeping-car ticket and boarded the night train.
Compound of 寝台 (shindai, 'bed' or 'sleeping berth') and 券 (ken, 'ticket').