"The PEB's (Presidential Emergency Board) recommendations remain the framework for an agreement," said the National Carriers' Conference Committee, which represents rails including Union Pacific, BNSF, CSX Corp CSX.O, Norfolk Southern NSC.N and Kansas City Southern KSU.N. A rail shutdown may freeze almost 30% of U.S. cargo shipment by weight, stoke inflation and cost the American economy as much as $2 billion per day. So far, six unions have ratified the tentative contract, which provides for significant wage increases, but sticking points remain over issues such as working conditions and time-off for sickness.