Union Pacific and Norfolk Southern said on Tuesday that they have agreed to a merger to create a $200 billion rail giant based on their current market capitalizations.

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.

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