Intermodal traffic increased 0.8% last week from a year ago, the Association of American Railroads reported.
Container traffic increased 1.3% to 200,077 units, but trailer traffic dropped 2.2%, to 32,104 units.
Railroad carloads excluding intermodal rose 1.4% for the week ended Saturday, to 291,909 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.