NEW YORK (Standard&Poor's) Nov. 15, 2011--Standard&Poor's Ratings Services said today that it has assigned its 'BBB+' issue-level rating on Norfolk, Va.-based Norfolk Southern Corp.'s issuance of $500 million in 3.25% senior unsecured notes due Dec. 1, 2021. The company will use the proceeds from the offering to fund general corporate purposes. The notes are senior unsecured obligations of Norfolk Southern, ranking equally with all other unsecured debt. Given the company's strong business profile, credit metrics as of Sept. 30, 2011, were strong for the rating. Adjusted funds from operations (FFO) to total debt was about 42%, and debt to total capital was 44%. The ratings on Norfolk Southern reflect its strong competitive position as one of