The definition of intermodal freight

Intermodal freight is when carriers use a mix of road transport and rail transport to haul freight, when it comes to continental shipments. For intercontinental shipments, maritime shipping is added. Intermodal transport is generally used to combined large volume of freight by common carriers, especially for longer distance hauls.

As most manufacturing companies and warehouses don’t have rail sidings, the initial pick ups and final segments of deliveries will be delivered by truck. The long distances segments of the freight hauls, are way more efficient when transported by rail. Freight can be either consolidated into box cars, or in cases where less handling (unloading and reloading) is desired, pre loaded containers can be piggy backed (double stacked) to maximize efficiency.

Needless to say, with one locomotive hauling dozens, and possibly hundreds of rail cars,  the saving in fuel and more importantly, driver pay, are the major catalyst for reduced shipping rates for large shipments using intermodal service.