overnight transportation service; late-night departure; red-eye flight
Refers to a scheduled transportation service (train, flight, bus, etc.) that operates late at night or overnight. Often used in travel contexts.
I booked an overnight service from Tokyo to Osaka.
The red-eye flight is comfortable because it's not crowded.
Compound of 深夜 (shin'ya, 'late night') and 便 (bin, 'service' or 'flight'). The exact historical derivation is uncertain, but the word follows a common pattern for naming transportation services.