NEW YORK (Standard&Poor's) June 6, 2012--Standard&Poor's Ratings Services said today that it has assigned its 'A-' issue rating to Union Pacific Corp.'s new $600 million senior unsecured notes due 2023 and 2042. Union Pacific will use proceeds from the notes for general corporate purposes, including the repurchase of common stock. The ratings on Omaha, Neb.-based Union Pacific reflect the favorable risk characteristics of the U.S. freight railroad industry as well as the company's solid competitive position, moderate financial policies, and strong liquidity. Price competition from other railroads and trucking companies on selected commodities and the company's high capital requirements, typical of the industry, somewhat offset these strengths. We characterize the company's business risk as "strong," its