Bulk material storage units that can be placed on flatbeds that can be hauled in various manners, including rail cars or trucks, to the destination and removed from the flatbed for temporary storage at the destination, freeing the transportation mode, e.g., rail cars or trucks, to be used elsewhere. Embodiments of the bulk material storage unit of the present invention replace rail hopper cars or truck trailers to hold the bulk material during transportation as well as provide temporary storage at the desired location, e.g., the origin or destination, without tying up transportation resources.