The Association of American Railroads (AAR) reported mixed weekly rail traffic for the week ending January 12, 2013, with U.S. railroads originating 279,893 carloads, down 6.4 percent compared with the same week last year. Intermodal volume for the week totaled 252,896 trailers and containers, up 10.4 percent compared with the same week last year. Thirteen of the 20 carload commodity groups posted increases compared with the same week in 2012, with petroleum products, up 47.7 percent; crushed stone, sand and gravel, up 17.5 percent, and lumber and wood products, up 15.5 percent. The groups showing a decrease in weekly traffic included iron and steel scrap, down 22.1 percent; metallic ores, down 18.6 percent, and coal, down 16 percent. Weekly carload volume on Eastern railroads was down 3.6 percent compared with the same week last year. In the West, weekly carload volume was down 8.1 percent compared with the same week in 2012. For the first two weeks of 2013, U.S. railroads reported cumulative volume of 521,575 carloads, down 9.1 percent from the same point last year, and 431,213 trailers and containers, up 1.9 percent from last year. Canadian railroads reported 75,982 carloads for the week, down 1.1 percent compared with the same week last year, and 53,908 trailers and containers, up 7.8 percent compared with 2012. For the first two weeks of 2013, Canadian railroads reported cumulative volume of 144,403 carloads, down 0.6 percent from the same point last year, and 95,909 trailers and containers, up 6.3 percent from last year. Mexican railroads reported 14,539 carloads for the week, up 19.6 percent compared with the same week last year, and 9,355 trailers and containers, up 6.1 percent. Cumulative volume on Mexican railroads for the first two weeks of 2013 is 22,940 carloads, down 1 percent compared with the same point last year, and 14,445 trailers and containers, down 10.9 percent from last year.  Combined North American rail volume for the first two weeks of 2013 on 13 reporting U.S., Canadian and Mexican railroads totaled 688,918 carloads, down 7.2 percent compared with the same point last year, and 541,567 trailers and containers, up 2.3 percent compared with last year.