For transport modes, atomization represents the smallest load unit that can be effectively transported. The individual is the smallest load unit for passenger transportation, while a parcel (box, bag, drum, pallet) or a part is the smallest load unit for freight transportation. Atomization is less relevant for bulk since the smallest load unit is a flexible concept; it can be subdivided without any changes in the characteristics of the product. Still, the smallest bulk trade transactions rarely go under a ton (except for retail, where the goods are bought in “bulk”). Massification for transportation modes involves the growing capacity to move load units in a single trip. The relationship between atomization and massification can be paradoxical, as individuals and customers often prefer the convenience of atomization. At the same time, carriers favor massification and the economies of scale it confers. Transportation systems are therefore a compromise between atomization and massification and the context-appropriate load unit for a given flow.
The passenger train is the most massified land passenger transportation mode, carrying about 1,000 passengers. In contrast, the Airbus A380, the largest operating passenger plane, has a standard configuration for about 550 passengers. Still, these massified forms are not suitable for a large share of passenger flows. The largest passenger conveyance is the cruise ship, with the biggest ships carrying about 7,000 passengers.
For bulk transportation, tanker ships can carry up to 400,000 tons, while some bulk carriers can carry up to 350,000 tons. These flows are suitable for the largest trades between importers and exporters and can only be handled by a limited number of terminal facilities. Containerization offers a unique advantage since the container is a relatively small (atomized) load unit that can carry, on average, 15 to 25 tons. In contrast, containers can be massified on large containerships, carrying up to the equivalent of 24,000 standard 20-foot containers.