Union Pacific and Norfolk Southern said their 6,692-page merger application is complete and urged regulators to reject rival railroads' efforts to delay the process, reports New York's FreightWaves.

BNSF, Canadian Pacific Kansas City, Canadian National and CSX argued the Surface Transportation Board should reject the filing, citing missing merger agreement details, insufficient competition analysis and lack of review of potential future mergers.

Union Pacific dismissed most of the claims as baseless or misguided. It said omitted material from the merger agreement only addressed regulatory risk and did not alter the transaction terms. UP added that disputes over privileged information should be handled through discovery, not by rejecting the application.

UP also countered claims about traffic diversion data, saying its workpapers included county-level detail on two million truckloads. It rejected suggestions that it should pay for data licences to support competitors' participation in the case.

Norfolk Southern focused on CSX's request for a separate proceeding over the Norfolk & Portsmouth Belt Line Railroad. NS said the request was an attempt to gain an advantage at the Port of Virginia and was unnecessary as the application already covered potential board rulings.

UP similarly said CSX's request for a separate proceeding on the Terminal Railroad Association of St Louis was unwarranted, noting the application committed to divesting NS's share to keep UP's post-merger ownership below 50 per cent.

The STB will now decide whether to accept the application. In 2021, the board initially rejected CSX's bid for Pan Am Railways before later approving a revised filing, while the Canadian Pacific-Kansas City Southern merger was accepted despite objections.