Intermodal traffic fell 1.3% for the week ended Saturday from a year ago, led by a decline in trailer traffic, the Association of American Railroads said.
Container traffic slipped 1.3% to 201,995 units from a year ago, while trailer traffic fell 7.1% to 31,946 units.
Railroad carloads excluding intermodal fell 0.4%, to 303,260 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.