Intermodal transportation

The standardized container made intermodal possible. A box built to ISO dimensions locks onto a vessel cell, a railcar, and a road chassis equally well, so freight can cross an ocean and a continent with the doors opened once, at destination. Capacity across the whole system is counted in TEU, and a typical ocean freight import is intermodal almost by definition: vessel to the port, then rail or truck inland.

The cost case is strongest on long inland legs. Rail moves a container for less per mile than a truck once the haul stretches past several hundred miles, which is why a box from Shanghai to Chicago typically rides rail from the West Coast rather than rolling the whole way on a chassis. The trade is variability: trains run on fixed schedules, containers can sit at ramps waiting for a slot, and a missed connection adds days, not hours.

Every intermodal move starts and ends with drayage, the short truck legs connecting ports and rail ramps to docks, and those legs cause a disproportionate share of the failures. Sound logistics planning treats intermodal transit as a range rather than a date and sizes inventory buffers accordingly.

Frequently asked questions

What is intermodal transportation?

Intermodal transportation moves freight in the same container across two or more modes, typically ship, rail, and truck, without handling the goods themselves at each transfer. The container is lifted between vessel, railcar, and chassis while the freight inside stays sealed, with the doors opened once, at destination. A typical ocean import is intermodal almost by definition: vessel to the port, then rail or truck inland.

When is intermodal cheaper than trucking?

The intermodal cost case is strongest on long inland legs, because rail moves a container for less per mile than a truck once the haul stretches past several hundred miles. In one example, moving 40-foot containers from the Port of Los Angeles to Dallas cost $3,100 by rail plus local drayage against $4,800 all-truck, about $425,000 a year across 250 containers, in exchange for two to three extra transit days.

What are the drawbacks of intermodal?

The trade in intermodal is schedule variability. Trains run on fixed schedules, containers can sit at ramps waiting for a slot, and a missed connection adds days rather than hours. Sound planning treats intermodal transit as a range rather than a date: one shipper planning 18 days port to door saw most boxes arrive in 17 to 21 days but some stretch to 26 during peak-season ramp congestion, so it carried an extra week of safety stock on those lanes.

What is drayage in an intermodal move?

Drayage is the short truck legs connecting ports and rail ramps to docks at the start and end of every intermodal move. Those legs cause a disproportionate share of intermodal failures despite covering the fewest miles, so they deserve specific attention in carrier selection and scheduling.