Combining Union Pacific and Norfolk Southern into the first transcontinental railroad in the U.S. would create a 52,215-mile colossus that could offer seamless service from coast to coast, bypassing longtime interchange choke points in Chicago and at gateways along the Mississippi River.

The Union Pacific and Norfolk Southern corporations announced Tuesday the companies will merge to create America's first transcontinental freight railroad.

Union Pacific is seeking to buy Norfolk Southern in an $85-billion deal that would create the first transcontinental railroad in the U.S.