AAR said just nine of the 20 carload commodity groups it measured posted increases compared with the same week in 2011. Leading gainers included motor vehicles and equipment, up 30.9%, petroleum products, up 25.6%, and metals and products, up 19.4%. Pacing the declining commodities were coal, down 13.1%, grain, down 11.9%, and nonmetallic minerals, down 10.8%.

Canadian carload freight traffic fared better, up 7.4% compared with the same week last year, but Canadian intermodal volume slipped 2.6%. Mexican freight carload volume fell 8.1% for the week ending Feb. 25, but Mexican intermodal rose 17.8%.

Combined North American carload freight volume for the first eight weeks of 2012 on 13 reporting U.S., Canadian, and Mexican railroads was up 0.7% measured against the comparable 2012 period, while intermodal was up 2.8%.