Intermodal freight transport combines the best attributes of both truck and rail shipping, and for long

distances, can cut fuel use and greenhouse gas emissions by 65%, compared to truck-only moves.

What is the challenge?

A single locomotive pulling 20 or more freight cars

can haul more freight than a truck hauling one to

three trailers. This makes trains more efficient than

trucks on a ton-mile basis. It also means using

freight trains to haul cargo has the potential to

provide significant greenhouse gas reductions.

However, trains generally have fewer capabilities to

bring freight “door-to-door” and have more limited

scheduling flexibility than trucks. The characteristic

swaying motion of train cars may harm certain

damage-sensitive freight. Because of these

distinctions, trucks move more than four times as

much freight as rail.

What is the solution?

Intermodal ground freight transport combines the

best of truck and rail modes. Freight trains carry

cargo over long distance, high volume rail corridors,

and trucks move the loads between the rail terminals

and the cargo’s ultimate origin or destination. 

Different intermodal options are available to fit a

variety of freight needs. Freight can be shipped via

“trailer on flat car,” commonly called TOFC, or

“piggyback.” In a TOFC move, reinforced truck

trailers mount on railroad flat cars or spine cars

(frame-like cars with a middle bar or spine) for the rail

leg of the trip, and hook to combination trucks for the

rest of the trip.

Oceangoing freight is commonly shipped in 40 foot

metal shipping containers. For the inland portion of

the trip, this freight can be shipped “container on flat

car” or COFC. The container is loaded on a railroad

flat or spine car for the rail leg of the trip, and onto a

container chassis (a frame-like truck trailer) for the

truck portion of the trip. The most efficient way to

move containers long distances over land is to

“double stack” them one on top of another onto a

railroad well car (rail cars with a “well” for the bottom

container.) Multiple double stack railroad well cars

may be permanently coupled together to decrease

stress and cargo damage during train braking and

acceleration. A universal railroad well car can also

handle unstacked trailers. 

Technological advances in freight rail cars have

expanded the opportunitiesintermodal freight moves.

One technology allows a truck trailer to travel on

railroad tracks. The trailer is backed onto the end of

a railroad track, positioned over two sets of railroad

axles and wheels (called bogeys), then lowered and

attached, so it functions as a railroad car. A second

innovation makes it possible to rail virtually any

standard truck trailer. In this option, trucks drive onto

a rail “car” that consists of 21 rigidly attached rail car

platforms, and unload trailers onto this platform.

Because the long, articulated platform has no slack

action, it can handle standard trailers, unlike TOFC,

which requires reinforced trailers.

Intermodal transport may not be suitable for all

goods. Time-sensitive products may require faster or

more flexible delivery than some railroads offer.

Damage-sensitive commodities may call for a

smoother ride than freight trains can provide.

However, rail car manufacturers are introducing

advanced suspension systems and car designs that

better stabilize, cushion and protect railed cargo.

The results are in . . . 

Intermodal is an attractive option for shipments over

500 miles. The economic and environmental benefits

of intermodal ground freight service are maximized

over long hauls, where the fuel and cost savings from

the rail part of the trip are high enough to recoup the

extra fuel and handling costs to transport and

transfer trailers and containers between trains and

trucks. For shipments over 1000 miles, using

intermodal transport cuts fuel use and greenhouse

gas emissions by 65 percent, relative to truck

transport, alone.

Next steps

Shippers, logistics providers, and trucking companies

should consider specifying intermodal transport when

arranging long distance freight shipments. Many

states have information about intermodal facilities

within their state transportation systems. State

department of transportation contact information can

be found at http://www.fhwa.dot.gov/webstate.htm.