Canadian National said it will sell a 70-mile rail line connecting Baton Rouge and New Orleans to help secure regulators' approval for its $33.6 billion acquisition of Kansas City Southern, a move that could maintain rail competition in the area and help efforts to connect the two cities with passenger rail.

The two rail companies filed a motion with the U.S. Surface Transportation Board Wednesday to set up a voting trust that would acquire Kansas City Southern and own the railroad while regulators review the deal.

The Baton Rouge to New Orleans line is the only area of overlap between the Canadian National and Kansas City Southern rail networks.