Intermodal Transport
Intermodal transport is the movement of freight using two or more modes of transportation — such as truck, rail, and ocean — without handling the cargo itself when changing modes. The goods remain in the same standardized container or trailer throughout the journey, transferring seamlessly between ships, trains, and trucks at interchange points.
The global intermodal freight transportation market reached approximately USD 27.5 billion in 2025 and is projected to grow to over USD 58 billion by 2031, driven by e-commerce growth, sustainability mandates, and the economic advantages of rail over long-haul trucking.
Intermodal transport uses a single loading unit (typically a container or trailer) that moves across multiple transportation modes without the freight being handled or repackaged at each transfer point.
How Intermodal Shipping Works
A typical domestic intermodal shipment in the United States follows a three-leg structure: truck–rail–truck. The process works as follows:
- Origin drayage: A truck picks up a loaded container or trailer from the shipper's facility and delivers it to a nearby intermodal rail terminal (ramp).
- Rail line-haul: The container is loaded onto a rail car — either stacked on a double-stack well car or placed on a flatcar — and transported over the long-distance corridor.
- Destination drayage: At the destination rail terminal, a truck picks up the container and delivers it to the consignee's facility.
For international shipments, the intermodal chain often begins with an ocean leg: a container moves by vessel from an overseas port, is discharged at a domestic port, drayed to a rail terminal, transported by rail inland, and finally delivered by truck.
For international intermodal shipments, the chain extends further:
Benefits of Intermodal Transport
Cost Advantages
Rail is significantly cheaper than trucking for long-distance freight. According to the International Council on Clean Transportation, the cost per ton-kilometer for rail is approximately $0.04, compared to $0.12 for trucking — making rail roughly three times more cost-effective on a per-unit basis for distances over 1,000 km.
Intermodal shipping becomes cost-competitive with over-the-road (OTR) trucking at distances of approximately 500–750 miles or more. Below this threshold, the added drayage costs and terminal handling fees can offset the rail savings.
| Factor | Intermodal (Truck + Rail) | Over-the-Road Trucking |
|---|---|---|
| Cost per ton-mile | Lower (long haul) | Higher |
| Break-even distance | ~500–750 miles | Any distance |
| Fuel price sensitivity | Lower | Higher |
| Capacity constraints | Less affected by driver shortages | Driver shortage impacts |
| Transit time | 1–2 days longer | Faster |
Environmental Benefits
Rail freight produces an estimated 75% fewer greenhouse gas emissions than long-haul trucking per ton-mile. According to EPA and Association of American Railroads (AAR) data, freight rail emits approximately 21.2 metric tons of CO₂ per million ton-miles, compared to 154.1 metric tons for trucks — roughly a 7:1 ratio.
For shippers with sustainability targets or Scope 3 emissions reporting requirements, shifting long-haul freight from truck to intermodal rail is one of the most impactful single actions available.
Many large retailers and consumer goods companies use intermodal for 40–60% of their domestic long-haul freight, citing both cost savings and carbon reduction targets in their sustainability reports.
Capacity and Reliability
The trucking industry faces a persistent driver shortage. Intermodal helps mitigate this by using rail for the long-haul segment, requiring truck drivers only for the shorter drayage legs. A single intermodal train can replace 280 or more trucks on the highway, reducing road congestion and wear on public infrastructure.
Intermodal vs Multimodal
These two terms are frequently confused but have distinct meanings with important implications for contracts, liability, and documentation.
| Aspect | Intermodal | Multimodal |
|---|---|---|
| Contracts | Separate contract with each carrier for each leg | Single contract (through bill of lading) covering the entire journey |
| Liability | Each carrier liable only for their leg | One party (the Multimodal Transport Operator, or MTO) liable for the entire journey |
| Responsibility | Shipper or freight forwarder coordinates between carriers | MTO coordinates all legs |
| Documentation | Separate documents per leg (e.g., truck BOL + rail waybill) | Single multimodal bill of lading |
| Pricing | Separate rates per segment | Single through-rate |
| Shipper visibility | More control over each leg | Simpler but less granular control |
Many people use "intermodal" and "multimodal" interchangeably. The key distinction is contractual: intermodal means separate contracts per carrier, while multimodal means one contract with one responsible party. This affects who you file a claim against if cargo is damaged.
In practice, the term "intermodal" in the U.S. domestic market almost always refers to containerized freight moving by truck and rail, regardless of the contractual structure. The intermodal/multimodal distinction is more strictly observed in international shipping.
Key Intermodal Infrastructure
Intermodal Terminals (Ramps)
An intermodal terminal or ramp is the facility where containers transfer between truck and rail. Major U.S. Class I railroads — BNSF Railway, Union Pacific, Norfolk Southern, and CSX Transportation — operate extensive networks of intermodal terminals across the country.
Key terminal operations include:
- Lift-on/lift-off (LoLo): Cranes lift containers from chassis onto rail cars and vice versa
- Gate processing: Trucks check in, containers are inspected, and paperwork is verified
- Grounding: Containers stored temporarily in the terminal yard before loading
Container Types
Intermodal containers come in two main varieties:
- ISO containers (20ft and 40ft): Standard international shipping containers that move across ocean, rail, and truck. Most commonly used in international intermodal.
- Domestic containers (53ft): Larger containers designed specifically for U.S. domestic intermodal service. These are wider and taller than ISO containers and cannot be used on ocean vessels.
Chassis Pools
A chassis is the wheeled frame onto which a container is mounted for road transport. Intermodal chassis are managed through:
- Carrier-owned pools: Railroad or steamship line provides chassis
- Intermodal Equipment Provider (IEP) pools: Third-party chassis leasing companies (e.g., DCLI, Flexi-Van)
- Shipper-owned chassis: Some large shippers maintain their own fleet
Chassis availability and condition are common pain points in intermodal operations, particularly at congested port-adjacent terminals.
Double-Stack Rail
Double-stack rail service — stacking two containers vertically on specially designed well cars — is one of the most significant innovations in intermodal freight. It effectively doubles the carrying capacity of each train without proportionally increasing fuel consumption or labor costs.
Intermodal Service Types
| Service Type | Description | Typical Use |
|---|---|---|
| COFC (Container on Flatcar) | Container placed on a standard flatcar | Older equipment, single-stack |
| TOFC (Trailer on Flatcar) | Entire truck trailer driven onto a flatcar ("piggyback") | Less common today |
| Double-Stack | Containers stacked two-high in well cars | Dominant domestic and international method |
| Expedited Intermodal | Premium rail service with guaranteed schedules and faster transit | Time-sensitive freight |
| Door-to-Door | Railroad or IMC arranges all drayage | Full-service intermodal |
| Ramp-to-Ramp | Shipper arranges own drayage to/from terminals | Cost-conscious shippers |
When to Use Intermodal
Intermodal is ideal when:
- Distance exceeds 500–750 miles — the rail savings outweigh drayage and handling costs
- Transit time flexibility of 1–2 days — intermodal is typically slower than OTR
- Freight is containerizable — standard dry goods, consumer products, non-perishable commodities
- Volume is consistent — weekly or daily container volumes justify the logistics setup
- Sustainability matters — ESG goals or customer requirements for lower-carbon shipping
Intermodal is less suitable for:
- Short-haul moves under 500 miles
- Time-critical or expedited freight
- Freight requiring temperature control (though reefer intermodal services exist)
- Oversized or overweight loads that don't fit standard containers
Resources
| Resource | Description | Link |
|---|---|---|
| Intermodal Association of North America (IANA) | Industry association for intermodal freight | intermodal.org |
| Association of American Railroads (AAR) | Rail industry data, safety, and policy | aar.org |
| Bureau of Transportation Statistics | U.S. freight transportation data and analysis | bts.gov |
| Surface Transportation Board (STB) | U.S. federal rail regulatory agency | stb.gov |
| EPA SmartWay Program | Freight sustainability benchmarking and tools | epa.gov/smartway |
Related Topics
- Drayage — the short-haul truck moves that connect intermodal terminals to shippers and consignees
- FTL vs LTL — understanding when over-the-road trucking is the better choice
- Container Types — ISO container specifications used in international intermodal
- Bill of Lading (BOL) — documentation used for the trucking legs of intermodal moves