美国最大铁路运营商联合太平洋公司（Union Pacific）对Norfolk Southern提出每股约320美元的收购报价。（彭博）

Group 1 - The core point of the article is that Union Pacific, the largest railroad operator in the United States, has made an acquisition offer of approximately $320 per share for Norfolk Southern [1] Group 2 - The acquisition bid indicates Union Pacific's strategic move to expand its market presence and consolidate its position in the railroad industry [1] - The offer price reflects a significant valuation of Norfolk Southern, suggesting confidence in the potential synergies and growth opportunities that could arise from the merger [1] - This development may trigger further consolidation in the railroad sector, as other companies may respond to the competitive landscape created by this bid [1]