Intermodal rail is a freight shipping method that moves standardized containers by train for the long-haul portion of a journey, then transfers them to trucks or ships for pickup and delivery, all without ever unpacking the cargo inside. The container itself travels between modes of transport, not the goods. This approach handled 14.06 million containers and trailers across U.S. railroads in 2025, making it one of the most heavily used freight systems in the country.
How Intermodal Rail Works
The basic idea is simple: a shipping container gets loaded once at its origin, then rides on whatever combination of truck, train, and ship makes sense for the route. For a typical domestic shipment, a truck picks up a loaded container from a warehouse or manufacturer and drives it to a nearby rail terminal. There, a crane lifts the container off the truck chassis and places it onto a rail car. The train carries it hundreds or thousands of miles to a terminal near the destination, where another truck picks it up and delivers it the final stretch.
The key distinction from traditional shipping is that nobody opens the container or handles the freight during these transfers. The container is the unit that moves between modes, which reduces damage, theft, and the labor costs of reloading cargo at every handoff point.
The Containers
About 90 percent of the world’s intermodal containers are standard rectangular steel boxes designed for dry freight. Globally, the most common sizes are 20 feet and 40 feet long, both 8 feet wide. These dimensions are set by international standards so the same container can ride on a ship from Shanghai, a train across the U.S., and a truck to a distribution center in Ohio without any modification.
North America has its own twist. Domestic containers are often 53 feet long and 102 inches wide, matching the maximum width allowed for trucks on American highways. These are about 6 inches wider than the global standard and typically aren’t built to withstand ocean shipping. They’re designed specifically for moving goods between rail and road within the continent. You’ll also find 45-foot and 48-foot versions, along with specialized types: refrigerated containers for perishable food, tank frames for bulk liquids, flat-racks for heavy machinery, and open-top units for oversized cargo.
Double-Stacking and Rail Cars
One of the biggest efficiency advantages of intermodal rail is double-stacking: placing two containers on top of each other on specially designed well cars. This doubles the carrying capacity of a train without making it any longer, which matters enormously when you’re running trains on congested rail corridors. Well cars have a recessed “well” that sits low between the wheel assemblies, allowing the bottom container to ride closer to the ground so the top container still clears bridges and tunnels.
Double-stacking also improves fuel efficiency. Trains carrying double-stacked containers experience roughly 9% less air resistance than they otherwise would, saving about half a gallon of fuel per mile per train. Over a 2,000-mile transcontinental route, those savings add up fast.
What Happens at the Terminal
Intermodal terminals are the hubs where containers change from one mode of transport to another. The equipment used depends on the terminal’s size and traffic volume. Smaller facilities might rely on reach stackers, which are essentially massive forklifts that can grab containers from the side and stack them three high. Straddle carriers look like giant metal frames on legs that drive over a container, lift it, and carry it to a rail car, truck, or storage stack.
High-volume terminals use gantry cranes. A rubber-tired gantry crane spans up to four rail tracks and transfers containers between trains and trucks. The largest terminals use rail-mounted gantry cranes that can reach across six to ten tracks at once. At port terminals where ships are involved, specialized cranes called portainers handle the loading and unloading of container vessels. Within the terminal itself, hostler trucks shuttle containers on wheeled chassis between staging areas.
The 500-Mile Rule
Intermodal rail generally becomes cheaper than pure trucking when the shipping distance exceeds about 500 miles. Below that threshold, the time and cost of transferring containers at terminals on both ends of the trip eat into whatever savings the train provides. Above it, rail’s fuel efficiency and ability to move enormous volumes at once start to dominate the math. A single intermodal train can carry the equivalent of several hundred truckloads, spreading fixed costs across far more freight.
This is why intermodal rail dominates long-haul corridors like Los Angeles to Chicago, or the ports of Long Beach and New York/New Jersey to inland distribution centers. For shorter routes, trucking remains faster and more practical since there’s no need to build in terminal transfer time on either end.
The Short Truck Trips: Drayage
The truck legs on either end of an intermodal journey have a specific name in the industry: drayage. These are short-distance hauls, typically under 100 miles, that connect ports, rail yards, warehouses, and distribution centers. A drayage truck picks up your container at a rail terminal and delivers it to its final destination, or vice versa at the start of the journey.
Drayage is often the most logistically complex part of an intermodal shipment. Rail terminals operate on train schedules, and containers need to arrive in time for loading or be picked up promptly after unloading to avoid storage fees. Coordinating these short truck trips with the longer rail schedule is a constant challenge for freight planners.
Environmental Benefits
Shifting freight from trucks to trains for the long-haul portion of a journey cuts carbon emissions by 60% to 70% compared to road-only transport. The advantage is especially pronounced for dense, heavy cargo. Trains are inherently more fuel-efficient than trucks because steel wheels on steel rails produce far less friction than rubber tires on asphalt, and a single locomotive can pull the equivalent of hundreds of truckloads.
These emission reductions depend partly on the ratio of rail distance to truck distance. The environmental benefit grows as the rail portion of the trip gets longer relative to the drayage legs on each end. For shipments where the truck connection distance is more than about 20% of the rail distance, the advantage starts to shrink.
Who Operates Intermodal Rail in North America
Seven Class I freight railroads handle the bulk of intermodal traffic in the U.S., Canada, and Mexico: BNSF Railway, Union Pacific, CSX Transportation, Norfolk Southern, Canadian National, Canadian Pacific, and Kansas City Southern. These carriers operate the long-haul rail corridors that connect coastal ports with inland markets and link major metropolitan areas across the continent.
U.S. rail container volume hit a record 13.65 million units in 2025, reflecting steady growth in domestic intermodal shipping. Total intermodal volume, including both containers and truck trailers carried on rail cars, reached 14.06 million units that year, the second-highest annual total on record. The growth is driven largely by e-commerce demand, supply chain diversification, and shippers looking to reduce both costs and emissions on long-distance routes.