Last month, Union Pacific said 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.

When Union Pacific and Norfolk Southern announced their merger deal Tuesday to form “America’s first transcontinental railroad,” it puzzled some who recalled the golden spike driven in 1869 at Utah’s Promontory Summit. That last spike only connected two railroads from Omaha, Neb., to Sacramento, Calif.

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.