A bipartisan group of U.S. Senators is urging the Surface Transportation Board (STB) to conduct a "rigorous and comprehensive" evaluation of the proposed mega-merger between Union Pacific Railroad and Norfolk Southern Railway.

UP announced the $85 billion deal to acquire Norfolk Southern in late July, and if it goes through, it would create the nation's first transcontinental railroad, and put 40% of U.S. rail freight in the hands of a single company. With the STB reviewing the proposal now, lawmakers from both sides of the aisle penned a letter on October 30, where they called on the board to remember its mandate to "preserve long-term competition and ensure efficient, economically viable rail service." 

"Already highly consolidated, the current landscape of railroads as it exists today represents a fragile equilibrium," the letter reads. "As the STB reviews the proposed merger, it is important to consider how additional consolidation could alter this equilibrium."

Senators also pointed to historical precedents, including the 1996 Union Pacific-Southern Pacific merger, which led to "widespread service breakdowns and safety lapses." According to one analysis from Wayne State University, the 1996 merger doubled rail freight transit times, while railroad performance deteriorated across nearly all metrics in the ensuing months, impacting service availability, on-time delivery and logistics costs. 

Others have voiced similar concerns over the proposed UP-Norfolk merger, with U.S. rail unions claiming in late August that the deal would be bad for both workers and shippers alike, and alleging that UP's "troubling safety record" should give regulators pause.

"There is no world where Union Pacific should be controlling a coast-to-coast rail network," Transport Workers Union president John Samuelsen said in a July 29 release. In one example highlighted by the TWU, the Federal Railroad Administration determined in May 2024 that UP managers had undermined government safety assessments in the wake of a string of derailments.

Further clouding the review process for the merger is the Trump administration's firing of STB Commissioner Robert Primus in August. Primus filed a wrongful termination lawsuit in early October, claiming that his removal "threatens the economic balance needed to keep our national freight network functioning properly." No explicit reason was offered by the White House regarding Primus' dismissal, beyond a brief statement claiming that he "did not align with the President's 'America First' agenda." President Donald Trump voiced support for the merger in September, as did Commerce Secretary Howard Lutnick weeks prior.