Union Pacific Corp. agreed to acquire Norfolk Southern Corp. in a $72 billion cash-and-stock transaction, forming the only US transcontinental railroad in what stands to be the industry’s largest deal ever.

Union Pacific said on Tuesday it would buy smaller rival Norfolk Southern in an $85 billion deal to create the first U.S. coast-to-coast freight rail operator and reshape the movement of goods from grains to autos across the country.

Union Pacific is seeking to buy Norfolk Southern in a $85 billion deal that would create the first transcontinental railroad in the U.S, and potentially trigger a final wave of rail mergers across the country.