Union Pacific and Norfolk Southern today announced an $85 billion deal to tie their networks together and create the first U.S. transcontinental railroad. The merged company — which will be called Union Pacific — will transform the U.

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 plans to acquire Norfolk Southern in a deal worth $85 billion, the freight railroad giants announced Tuesday. If approved, the merger would create the nation’s first transcontinental railroad,