Complete Guide to Intermodal Shipping

Intermodal shipping — using two or more modes of transportation (typically truck and rail) in a single freight movement — is one of the most underutilized cost-saving strategies available to shippers. On lanes over 750 miles, intermodal can save 10-30% compared to over-the-road (OTR) trucking while reducing your carbon footprint by up to 75%.

This guide explains how intermodal works, when it makes sense, the equipment and logistics involved, and how to integrate intermodal into your transportation strategy.

How Intermodal Works

An intermodal shipment has three legs:

• Origin drayage: A truck picks up the loaded container or trailer at the shipper's facility and delivers it to a nearby rail ramp (intermodal terminal). This leg is typically 25-75 miles.
• Rail linehaul: The container rides on a train from the origin ramp to the destination ramp. This is the longest leg and where the cost savings happen — rail is 3-4x more fuel-efficient than trucking per ton-mile.
• Destination drayage: A truck picks up the container at the destination rail ramp and delivers it to the receiver's facility. Again, typically 25-75 miles.

The entire movement uses a single container, so the freight is loaded once and unloaded once — there is no rehandling at the intermodal terminals. The container is simply lifted from the chassis to the rail car and back.

Intermodal Equipment Types

Two primary equipment types are used in domestic intermodal:

• Containers (domestic): 53-foot steel containers designed specifically for domestic intermodal. They ride on rail well cars and are transferred to a chassis for the drayage legs. Domestic containers have the same interior dimensions as a standard dry van trailer.
• TOFC (Trailer on Flat Car): A standard 53-foot trailer is driven onto a rail flat car for the linehaul leg. Less common than container-on-flat-car (COFC) because it is less space-efficient on the train, but it eliminates the need for a chassis at origin and destination.
• International containers: 20-foot and 40-foot ISO containers used for import/export freight. These are smaller than domestic 53-foot containers and require chassis designed for their specific size.

When Intermodal Makes Sense

Intermodal is not right for every shipment. It works best when:

• Distance exceeds 750 miles: The rail linehaul cost advantage increases with distance. Below 500 miles, OTR trucking is usually cheaper because drayage costs at both ends eat into the rail savings.
• Transit time flexibility of 1-3 days: Intermodal typically adds 1-3 days of transit compared to OTR. If your customer needs next-day delivery, intermodal is not the answer. If they can accept a delivery window, intermodal saves money.
• Origin and destination are near rail ramps: Long drayage legs (100+ miles) reduce or eliminate the intermodal cost advantage. Ideally, both your facility and your customer are within 50 miles of a major rail ramp.
• Freight is non-perishable and not time-critical: While refrigerated intermodal containers exist, the added transit time and temperature-monitoring complexity make intermodal less common for perishable goods.
• Consistent volume: Intermodal pricing favors shippers with consistent, predictable volume. One-off shipments get spot rates that may not be much cheaper than OTR.

Intermodal Cost Comparison

Managing Drayage

Drayage — the short truck hauls to and from rail ramps — is where most intermodal problems occur:

• Chassis availability: Containers need a chassis (wheeled frame) for road transport. Chassis shortages at busy ramps can delay pickup and delivery. Work with drayage providers who maintain their own chassis pools.
• Ramp appointments: Rail terminals have specific windows for container drop-off and pickup. Missing a ramp appointment means your container sits until the next available window.
• Per diem and demurrage: If you hold a container or chassis beyond the allotted free time (typically 1-2 days), you will incur daily per diem charges of $50-$150. Unload containers promptly and return equipment quickly.
• Use local drayage experts: National OTR carriers are often not the best drayage providers. Local drayage companies know the ramp procedures, have relationships with terminal staff, and can navigate the congestion more effectively.

Major Rail Networks

The US intermodal rail network is operated by seven Class I railroads: BNSF, Union Pacific, CSX, Norfolk Southern, Canadian National, Canadian Pacific Kansas City, and Kansas City Southern. BNSF and Union Pacific dominate the western US, while CSX and Norfolk Southern serve the eastern US. The strongest intermodal lanes run east-west (LA to Chicago, Chicago to the Northeast) where rail distances closely match truck distances.

Getting Started with Intermodal

If you have not used intermodal before, start by identifying your highest-volume lanes over 750 miles and checking whether both ends are within 50 miles of a rail ramp. A freight dispatch partner can analyze your lane data, compare intermodal vs. OTR costs, and manage the drayage coordination so you get the savings without the operational complexity. Request a quote to see where intermodal fits in your freight strategy.

Frequently Asked Questions