Abstract: A carrier unit adapted to be converted into a bulk material carrier including a container having a floor and two parallel substantially vertical walls. The floor has at least one floor panel movable between a storage position and an operative position and at least one floor section movable between a storage position and an operative position. The floor panel when in the operative position and the floor sections when in the operative position cooperate with portions of the walls to define a compartment and to form an opening in the floor, which communicates with hoppers depending from the floor. A flexible liner is mountable in the compartment, when the floor panel and the floor sections are in the operative positions, for holding bulk material. The flexible liner includes an inlet for charging bulk materials into the liner compartment and an outlet cooperable with the opening for communicating the interior of the liner compartment with the exterior of the compartment for discharging the bulk materials.