The merger would create the United States’ first coast-to-coast rail network, spanning 50,000 miles and 43 states.

Union Pacific is seeking to buy Norfolk Southern in a $85 billion deal that would create the first transcontinental railroad in the U.S.

The blockbuster deal raises the odds that Buffett’s Berkshire Hathaway, which owns the Burlington Northern Santa Fe railroad, will reach a deal with CSX to create a second transcontinental railroad. Union Pacific and BNSF compete in the western U.S., while CSX and Norfolk Southern are the two big Eastern railroads.