The economic and environmental benefits of intermodal 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 1,000 mi., using intermodal transport cuts fuel use and greenhouse gas emissions 65%, relative to truck transport alone, according to EPA.
Technological advances in freight rail cars have expanded the opportunities for 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 typical trailer-on-flatcar moves, which require reinforced trailers.
Intermodal transport is not suitable for all goods. Time-sensitive products require faster or more flexible delivery than most railroads offer and 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.
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.