A shipping container chassis is a specialized trailer frame with wheels, axles, and locking pins. It has no deck plates or walls. It exists solely to carry standard ISO steel shipping containers. Marine terminals and rail yards place the container directly onto the chassis beams using overhead cranes. The chassis twist-locks clamp the container corners to hold it secure.
Chassis are the workhorses of drayage hauling. Because container terminals own massive pools of these frames, drivers often pick up a chassis, pull it to a ship dock, and load a container. A common problem is chassis maintenance. Since they are shared among thousands of drivers, issues like bad lights, worn tires, and faulty brakes are common, requiring careful inspection before leaving the port gates.