Two of the largest US railroads, Union Pacific and Norfolk Southern, announced on Tuesday a plan to combine in a $72 billion deal that would create America’s first transcontinental freight railroad.

Union Pacific Transcontinental Railroad will strengthen U.S. supply chain, economy, and domestic manufacturing; preserve union jobs.

Union Pacific wants 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.