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.

Union Pacific is seeking to buy Norfolk Southern in a deal valued at $85 billion in a merger that could trigger the final wave of railroad mergers across the country.