Berkshire-Backed BNSF Warns Rail Megamerger Risks Higher Prices

The leader of BNSF Railway Co. warned that the proposed deal to combine two of its rivals risks pushing up costs for customers, a sign of industry opposition to the largest tie-up in US railroad history.

Katie Farmer, BNSF’s chief executive officer, said Wednesday the industry should question whether it’s an “accurate premise” that Union Pacific Corp.’s proposed $72 billion takeover of Norfolk Southern Corp. will lead eventually to double-digit growth in shipping volume for the combined company.

She suggested the combined company would increase prices if that growth fails to materialize as expected, pointing to Union Pacific’s ...