Chassis
What is a chassis?
A chassis is the wheeled steel frame, with its own axles, brakes and lights, that carries a shipping container over the road between port, rail ramp and warehouse. In the US most chassis come from pools or leasing companies and are billed per day from out-gate to return, so the chassis has to be found, inspected, available in the right size (20-foot, 40-foot, 45-foot or extendable) and returned before the days add up.
Why it shows up on invoices
- Chassis usage: billed per day from out-gate to return, with free days only where the contract grants them.
- Availability: a container ready to move with no chassis is not moving; someone pays for the wait.
- Inspection: a chassis with a defect cannot go (and should not); the repair time is on someone's clock.
- Pool rules: marine pool chassis carry their own terms, separate from the line's container terms.
Tracking them
A yard that cannot say which chassis is on the lot, which container it carries and who took the last one out is guessing at charges it will later be billed for. The identifier on the chassis, recorded at the gate with the container it is paired to, is what turns per diem disputes into lookups.