Intermodal traffic rose 5.8% last week compared with a year ago, though trailer traffic was down slightly, the Association of American Railroads reported.
Traffic totaled 213,486 units, led by a 7.2% gain in containers to 181,876 units. Trailers slipped 1.5% to 31,610 units.
U.S. railroads originated 282,987 carloads for the week ended Saturday, up 7.5%, 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.