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.

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.