Merger efforts of two of the US's major railroads, namely Union Pacific and Norfolk Southern, have recently faced a roadblock relating to missing documents in their acquisition application.

The deal is currently under increasing pressure after competitors BNSF Railway and Canadian National told the US Surface Transportation Board (STB) that the two railroads are withholding essential documents linked to their proposed transcontinental merger.

In a report by Freight Waves, the documents in question are necessary for rival carriers, shippers, and regulators to conduct a full assessment of the proposed deal.

BNSF and Canadian National stated that the regulator cannot properly evaluate the merger’s potential effects on market competition without broader access to internal records.

They argued that the information delivered so far does not sufficiently explain the reasoning behind the merger or allow a full review of possible consequences, and asked the STB to either halt or restart the review timetable.

In a further development, the STB board has recently ruled unanimously that the merger application filed by Union Pacific the previous month is “incomplete.”

According to the Journal of Commerce, the ruling blocks current progress, but the companies may correct the identified deficiencies and submit an updated application at a later date.

If the deal is passed, the proposed UP-NS merger offers significant benefits for rail cargo transport and port connectivity by creating an integrated, end-to-end network that eliminates interline complexities.

The single-line services offered by the merger will likely streamline operations, reduce delays, and improve reliability across the US. The enhanced connectivity could also shorten transit times along major corridors and strengthen coast-to-coast service, making intermodal links to ports faster and more efficient.