Intermodal traffic increased 0.8% last week from a year ago, the Association of American Railroads reported.
Container traffic rose 4% to 206,615 units, while trailer traffic slipped 1% to 33,910 units.
Railroad carloads excluding intermodal declined 2% for the week ended Saturday, to 292,812 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.