AAR said 10 of the 20 carload commodity groups it tracks posted increases compared with the same week in 2012, including with petroleum products, up 56%, farm products excluding grain, up 16.9%, and primary forest products, up 12%. Among the declining groups were metallic ores, down 20.4%, iron and steel scrap, down 16.8%, and coal, down 14.6%.

Canadian freight carload volume did better, up 0.5% compared with the same week last year, while Canadian intermodal showed strength, up 11%. Mexican freight carload volume also was robust, up 10.5% for the week ending Jan. 26 compared with a year ago, while Mexican intermodal rose 8.8%.

Hindered by the negative impact of U.S. freight carload volume, combined North American freight carload volume for the first four weeks of 2013 on 13 reporting U.S., Canadian, and Mexican railroads was down 4.7%. With all three nations recording gains in intermodal volume, combined North American intermodal volume notched a 5.1% gain over the comparable period in 2012.