Tim Boyle/Bloomberg News
Intermodal volume rose 3.7% for the week ended Aug. 17 from the same week a year ago, the Association of American Railroads reported.
Traffic increased to 256,458 trailers and containers, AAR said in its weekly report.
Rail carload traffic rose 0.5% to 295,901 year-over-year, the rail trade group said.
Four of the 10 carload commodity groups tracked by AAR posted increases, led by petroleum and petroleum products, which jumped 19.6%. Commodities showing a decrease included grain, which fell 8%.
For the first 33 weeks of the year, U.S. railroads moved 8 million intermodal containers and trailers, up 3.5% from last year. Carload traffic dipped 1.2% to 9.1 million units.