Union Pacific is reportedly considering acquiring a rival railroad, sending shares of CSX and Norfolk Southern higher.

NSC merger would significantly expand Union Pacific's rail network, potentially challenging the dominance of BNSF Railway, which Berkshire Hathaway acquired in

The rails sector is on high alert following reports that Union Pacific (UNP) is focused on acquiring Norfolk Southern (NYSE:NSC), which could create the nation's first coast-to-coast rails network if the deal cleared regulatory and White House scrutiny.