Intermodal traffic jumped 18% last week, the Association of American Railroads reported.
Traffic for the week ended Saturday rose to 237,006 trailers and containers, led by a 19.4% gain in containers, the group said.
Container traffic increased to 202,239 units, while trailers rose 10.7% to 34,767 units. The weekly total was also 18% higher than the same week two years ago, AAR said.
U.S. railroads originated 305,000 carloads for the week, the second straight high for the year.
That was 6.9% higher than the same week a year ago, and comparable to the same week of 2008, 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.