The combination of two large rail companies would create the first coast-to-coast network, but the deal could reduce competition.

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.

Railroad operator Union Pacific ($UNP) has confirmed that it is in advanced talks to merge with rival Norfolk Southern ($NSC) in what could become