One box, several modes
Instead of unloading individual packages from one vehicle to another, a container can travel by ship, rail, and truck as a single unit.
Double-stack trains
Special well cars allow many routes to carry one container above another, increasing the amount of freight moved per train where clearances permit.
Ports and inland terminals
Intermodal rail links seaports with large inland terminals where containers transfer between trains and trucks.
Why it matters
Containerization connected U.S. railroads directly to global manufacturing and retail supply chains. Many everyday consumer products spend part of their journey on a train.