M erger talk is swirling around Union Pacific Corp. and Norfolk Southern Corp. in a deal that could create a railroad mega-carrier and a huge transcontinental network spanning the U.S.

Union Pacific and Norfolk Southern are in merger talks to create the largest railroad in North America that would connect the East and West Coasts.

Union Pacific , the largest U.S. freight railroad operator, is exploring a possible acquisition of Norfolk Southern to create a $200 billion coast-to-coast rail network, a person familiar with the matter said.