^SmartWay
Transport Partnership
U.S. ENVIRONMENTAL PROTECTION AGENCY
A Glance at
Clean Freight Strategies
Intermodal Shipping
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 opportunities intermodal 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 thefuel 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.
U.S. Environmental Protection Agency • Office of Transportatli
February 2004. EPA420-F-03-026. • For more Information,, visit: www.epa.gov/smartway
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