Intermodal transport: What is it and how does it work?

Moving freight across long distances and international borders almost always requires more than one mode of transport. That’s the essence of intermodal transport – a necessary, integrated part of modern supply chains. Whether goods are moving from a factory to a port, across the ocean, or from an import terminal to a warehouse, intermodal is the default setup for containerised freight.

This article breaks down how intermodal shipping works and the key factors to consider when managing different transport legs and logistics configurations.

What is intermodal shipping?

Intermodal shipping is the transport of goods using two or more different modes of transportation – such as ships, barges, trains, and trucks – with cargo carried in a sealed shipping container throughout. The cargo itself is not handled during modal transfers – improving security, reducing damage risk, and minimises labour costs.

Intermodal is essential to nearly all ocean freight shipments. Ports are rarely the origin or end destination; containers must be moved to and from ports by road, rail, or barge. This inland movement – paired with the ocean leg – constitutes intermodal transport.

But intermodal isn’t limited to ocean freight. It also applies to air cargo, which involves ground transport before and after the flight and uses specially designed containers and pallets. Even land-based supply chains – combining rail and truck, for example – can be intermodal when goods move across modes without being unpacked.

The real value of intermodal logistics lies in combining the strengths of each mode to enable reliable, cost-effective, and scalable freight movement.

Intermodal vs multimodal: What’s the difference?

Both intermodal and multimodal transport involve moving goods using two or more modes of transport – but they have traditionally been differentiated by how the journey is managed and who holds responsibility.

• Intermodal transport typically involves multiple contracts. The shipper coordinates each leg separately – for example, booking trucking, rail, and ocean freight independently – while the cargo remains in the same container throughout
• Multimodal transport, on the other hand, is managed under a single contract with one logistics provider who oversees the full journey. The cargo may stay in one container or be handled between modes, depending on the setup.

This distinction is becoming less rigid, however. Recognising the value of unified coordination, end-to-end visibility, and streamlined communication, logistics providers are now offering intermodal services that function much like multimodal solutions. Under these offerings, the provider takes on full responsibility – managing multiple legs across modes under a single contract – while retaining the operational advantages of intermodal container continuity.

Modal combinations in intermodal transport

Intermodal freight often combines ocean shipping with inland transport modes such as rail, truck, or barge. The right configuration depends on distance, infrastructure access, cargo type, and speed requirements. Here are the most common intermodal combinations:

1. Ocean + truck

   Combines ocean freight with road transport for final delivery or drayage. Best for shorter inland distances, areas without rail access, and freight with flexible delivery schedules.

2. Ocean + rail

   Pairs ocean freight with long-haul rail for efficient inland distribution. Offers cost savings for high-volume moves, provided rail infrastructure is accessible.

3. Rail + truck

   Used for inland or domestic transport when the main leg is rail, supported by flexible truck haulage for first- or last-mile delivery. Ideal for reaching areas not directly connected by rail.

4. Ocean + barge

   Links ocean shipping with inland water transport. Particularly useful in regions with navigable rivers and for heavy or bulk cargo that benefits from barge efficiency.

5. Truck + barge

   Supports transport between barge terminals and inland destinations by road. Useful in regions with river access but limited rail infrastructure.

When and why intermodal transport delivers value

Intermodal transport brings tangible advantages. The combination of multiple modes – especially when integrated by a single provider – enables shippers to optimise cost, improve reach, and maintain flexibility across geographies and supply chain demands.

Here are some key benefits of intermodal configurations:

Lower costs over long distances

A manufacturer located far from a major port – for example, in central North America – can combine rail and truck to move goods more economically than road alone. Rail reduces fuel use and cost per ton-mile, especially for heavy shipments.

Efficient movement of large volumes

Intermodal is ideal for transporting high-volume, non-fragile cargo like building materials, packaged food ingredients, or industrial parts. Keeping the cargo in a single container across modes reduces handling, speeds up transfers, and minimizes damage risk.

Better use of infrastructure and faster delivery

A European retailer importing from Asia might combine ocean freight to Rotterdam, rail to a hub like Duisburg, and final delivery by truck. This type of intermodal route can bypass congested ports, shorten inland delivery times, and reduce total logistics cost.

Whether you're optimising for speed, scale, cost, or sustainability, intermodal offers a flexible, proven model that adapts to your supply chain needs.

Documentation requirements for intermodal shipping

Intermodal shipments require:

• A bill of lading (B/Ls) covering the full journey or leg-specific movements
• Customs documents, permits, and duty information for international moves
• Where air freight is included, an air waybill (AWB)
• Where cargo is moved under customs control (e.g., bonded shipments), coordination with the bonded warehouse

Key factors to consider when managing intermodal freight

Cost vs transit time

Using ocean, rail, or barge for the primary leg of an intermodal shipment typically reduces costs; while urgent shipments will benefit from the reduced transit times enabled by air or direct trucking. The key is to balance your priorities – whether optimising for cost, speed, or reliability.

Cargo type and value

In nearly all cases, containerised cargo – whether dry or refrigerated – completes its journey through intermodal transport.

Certain cargo types benefit from tailored configurations:

• Fragile or high-value goods may favour shorter transit times and lower risk of damage enabled by air freight.
• Temperature-sensitive, hazardous, or oversized cargo may face mode-specific restrictions or require specialised infrastructure.

Cargo should be well packed, securely stowed, and properly documented to withstand multiple handling points between modes.

Infrastructure availability

Intermodal operations depend on the availability and quality of infrastructure – including ports, rail yards, barge terminals, inland depots, and road access.

Evaluate the reliability of transfer points, route options, and any congestion issues to plan effectively and minimise disruptions.

Operational complexity and visibility

Predictable schedules and strong coordination are essential. Consider choosing a single logistics partner that offers:

• Real-time tracking across all legs
• Local expertise across all key transit hubs
• Proactive communication
• End-to-end service models to reduce handoffs and streamline execution

Need help navigating intermodal options?

Intermodal transport is the foundation of global supply chains. What matters is how you manage it: choosing the right modal combinations, ensuring documentation is accurate, and working with a provider that delivers seamless coordination from origin to destination.

At Maersk, we offer both intermodal carrier haulage and intermodal multi-carrier services, tailored to your operational needs and contract structure. For support on choosing the right configuration of intermodal transport options to meet your requirements, reach out to our team of intermodal experts.