Union Pacific Railroad has said it will refile its application to acquire Norfolk Southern Railway within weeks after regulators deemed the original submission incomplete, reports New York's Journal of Commerce.

UP CEO Jim Vena told the railroad's fourth-quarter earnings call the company was disappointed the US Surface Transportation Board required more information after nearly 7,000 pages were submitted. He said the response would take a few weeks to prepare and the merger was still on track to close in the first half of 2027.

Once resubmitted, the STB will restart a 30-day review period to determine if the filing is complete, allowing interested parties to comment. Mr Vena said a revised application could be sent in March.

Regulators cited insufficient information on future growth and inconsistencies in baseline assumptions. Opponents of the US$85 billion deal argued UP's projections, including removing two million truckloads from highways through 1.17 million truckload-to-intermodal conversions within three years, were overly optimistic.

Mr Vena said long-haul intermodal routes over 2,000 miles have lower rail market share due to handoffs in hubs such as Chicago. He argued a combined UP��S network would resemble shorter lanes of 1,000 to 1,500 miles where rail penetration is higher.

Other railways said handling that volume would require UP to run up to 15 more trains per day, risking congestion. Mr Vena countered that adding 10 to 15 trains was a small impact compared with the 2,000 daily movements already on the network.

UP also addressed the STB's objection to its failure to disclose Schedule 5.6, a document outlining conditions under which the company could walk away from the deal. He said he disagreed with the requirement but would comply.

Away from the merger, UP executives offered a cautious outlook for 2026. Chief financial officer Jennifer Hanneman said economic estimates for industrial production, housing starts and auto sales had deteriorated, with rail inflation expected to exceed four per cent.

UP said international intermodal traffic would likely decline through the first half of 2026, though domestic intermodal remained strong after record volumes in 2025. The railway gained market share from rival BNSF in California and won freight from the truckload sector, including contracts with Uber Freight.