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.

Merger 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.