Feb 24 Standard & Poor's Ratings Services said today that it has assigned its 'BBB' issue-level rating to CSX Corp.'s $300 million senior notes due 2043. CSX will use net proceeds from the debt issuance to fund a $275 million contribution to its qualified pension plans as well as for general corporate purposes, which may include repayment of debt, repurchases of CSX's common stock, capital expenditures, working capital requirements, productivity improvements, and other cost reductions at CSX's m