AAR said 12 of the 20 carload commodity groups it measures posted increases compared with the same week in 2011, led by farm products excluding grain, up 55.1%, petroleum products, up 52.6%, and lumber and wood products, up 16.6%. Declining commodity groups included metallic ores, down 26.8%, iron and steel scrap, down 21%, and coal, down 16.9%.

Canadian freight carload traffic for the week mimicked the U.S. category, though less severely, down 3.7% compared with the same week last year. Canadian intermodal volume, by contrast, rose 10.7% for the week. Mexican freight carload traffic rose 5.7% compared with the same week last year, while Mexican intermodal advanced 37.7%.

Combined North American rail volume for the first 41 weeks of 2012 on 13 reporting U.S., Canadian, and Mexican railroads was down 1.6% percent compared with the same period in 2011, while combined North American intermodal volume was up 4.7%.