Rail and intermodal traffic both declined for the week ended Saturday compared with a year ago, the Association of American Railroads said.
Intermodal traffic fell 3.1%, led by a 3.5% drop in container traffic to 181,614 units. Trailers fell 2% to 48,823 units.
Overall rail traffic dipped 0.6% for the week, to 334,821 carloads, the group 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.