noun
sleeping car; sleeper train
A train carriage with sleeping berths. The term is a direct loan from English 'car sleeper'.
夜行のカースリーパーで東京から大阪まで移動した。
I traveled from Tokyo to Osaka on an overnight sleeper train.
Variant spelling with a middle dot; less common but still seen.
寝台車 is the native Japanese term for a sleeping car, while カースリーパー is a less common loanword.
Loanword from English 'car sleeper'.