AAR said just nine of the 20 carload commodity groups it measures posted increases compared with the same week in 2011, led by petroleum products, up 46.3%, crushed stone, sand, and gravel, up 10.8%, and food and kindred products, up 10.3%. Declining commodity groups farm products excluding grain, down 22.7%, metallic ores, down 21.3%, and waste and nonferrous scrap, down 19.5%. Coal fell 9.7%.

Canadian freight carload volume for the week ending Sept. 15 did well, up 4.1% compared with a year ago. Canadian intermodal also rose, up 7.4%. Mexican freight carload volume for the week advanced 8.4% compared with the same week a year ago, while Mexican intermodal volume soared 28% above last year's level.

Combined North American freight carload volume for the first 37 weeks of 2012 on 13 reporting U.S., Canadian. and Mexican railroads was down 1.3% measured against he comparable period in 2011. Combined North American intermodal for the same period was up 4.7% compared with 2011.