CSX is acquiring a regional railroad in New England to bolster its network in the northeastern United States, but a rival railroad says the deal could hurt competition.

The Berkshire Eagle reports  CSX said Monday it is acquiring Pan Am Railways, but it didn't disclose terms of the deal. The transaction will expand CSX's 23-state network into Vermont, New Hampshire and Maine while adding to its reach in New York, Connecticut and Massachusetts.

If regulators approve the deal, CSX would also acquire Pan Am's partial ownership of a 600-mile joint venture with Norfolk Southern railroad called Pan Am Southern. Earlier this month, Norfolk Southern raised concerns about this deal with the Surface Transportation Board because it said allowing CSX to buy Pan Am could undermine competition between CSX and Norfolk Southern in the eastern United States.

If the deal is approved, Pan Am, which is based in North Billerica, Massachusetts, would become part of Jacksonville, Florida-based CSX.