Intermodal traffic increased 1.2% last week from a year ago, the Association of American Railroads reported.
Container traffic increased 1.6% to 197,833 units, but trailer traffic declined 1.5%, to 32,491 units.
Railroad carloads excluding intermodal dipped 0.3% for the week ended Saturday, to 281,387 units, AAR said in its weekly report.
Railroad volume is considered an important economic indicator. Intermodal traffic, which tends to be higher-valued merchandise than bulk commodities, uses trains for the long haul and trucks for the shorter distance at either end of the trip.