The nation's railroads moved more intermodal volumes last week than in any other week so far this year, the Association of American Railroads (AAR) said Thursday.

Intermodal volume on U.S. railroads for the week ending Aug. 14 was reported at 233,767 total trailers and containers, up 20.8 percent from the same week in 2009, but down 1.4 percent compared with 2008, AAR said.

Weekly container volume, a subset of intermodal, was the highest on record, up 22.4 percent compared with the same week in 2009, and up 6.4 percent compared with the same week in 2008, AAR said. Trailer volume, the other subset of intermodal, rose 12.3 percent last week compared with the same week in 2009, but fell 31 percent compared with 2008, according to the group.

Non-intermodal carload traffic continued to show moderate weekly gains, AAR said, with 295,948 carloads originating last week, up 7.1 percent compared with the same week in 2009, but down 11.3 percent from the same week in 2008.

Carload volume on Eastern railroads was up 6.4 percent from the same week last year, but down 12.8 percent from 2008, AAR said. In the West, carload volume was up 7.6 percent from the same week last year but down 10.2 percent from two years ago.

For the first 32 weeks of 2010, U.S. railroads reported cumulative volume of 9,041,726 carloads, up 7.2 percent from 2009, but down 13.1 percent from 2008; and 6,783,820 trailers or containers, up 13.9 percent from 2009, but down 5.7 percent from 2008.