freight service; cargo flight; freight train
Refers to a transportation service (flight, train, ship, truck) that carries cargo rather than passengers. Often used in compound terms like 貨物便で送る (send by freight).
I'll send this package by freight service.
The cargo flight arrived at night.
貨物列車 specifically means a freight train; 貨物便 is a broader term covering any cargo transport service.
Compound of 貨物 (cargo, freight) and 便 (service, mail, flight). The combination straightforwardly means a cargo transport service.