There are only a few sleeper trains left in Japan and they are what we call cruise trains. These luxury trains are mainly for rich people to enjoy.
この場合、次のような言い方ができますよ。
ーThere are only a few sleeper trains left in Japan and they are what we call cruise trains. These luxury trains are mainly for rich people to enjoy.
「日本にはほんのわずかな寝台列車しか残っておらず、それらはクルーズトレインと呼ばれています。この豪華な列車は主にお金持ちの人たちが楽しむためです」
sleeper trains で「寝台列車」
luxury で「豪華な」
ご参考まで！
Nowadays, most sleeper trains have become cruise trains, primarily serving as a luxury for the wealthy.
Nowadays, most sleeper trains have become cruise trains, primarily serving as a luxury for the wealthy.
Most overnight trains are now luxury cruise trains, mainly enjoyed by affluent travelers.
・primarily serving as a luxury
「主に贅沢品（たしなみ）として機能している」という意味です。単なる移動手段（transportation）ではなく、趣味や娯楽としての側面を強調できます。
カナダ 
アメリカ合衆国 
