U.S. intermodal traffic rose 3.6% for the week ended Saturday from a year ago, the Association of American Railroads said.
Trailer traffic declined 9% to 31,112 units, but containers rose 5.7% to 211,660 units, the rail trade group said in its weekly report.
Railroad carloads excluding intermodal declined 6.2% to 286,962 units, the group said.
For the month of March, intermodal traffic rose 3.5% to 928,350 units, while rail traffic fell 5.8% to 1.12 million carloads.
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.