Intermodal rose 13.6% last week from a year earlier, the Association of American Railroads said.
Traffic for the week ended Saturday totaled 235,606 trailers and containers, led by a 14.6% jump in containers to 207,401 units. Trailers rose 8.2% to 34,136 units.
Excluding intermodal shipments, U.S. railroads originated 302,855 carloads for the week, 9.6% higher than a year ago, AAR said.
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.