Union Pacific reported a robust second-quarter adjusted profit of $1.8 billion, or $3.03 per share, exceeding Wall Streetโs expectations amid ongoing merger speculation with rival Norfolk Southern, the smallest of the six major US freight railroads.The Omaha-based rail giant said its operating revenue grew 2% year-on-year to $6.2 billion. Analysts had expected earnings of $2.91 per share, according to consensus estimates. The company had reported a profit of $2.71 per share in the same period last year, AP reported.Union Pacific shares rose about 1% in premarket trading on Thursday to $233.30. The stock had dipped to a 2025 low of around $208 in April, amid fears triggered by President Donald Trumpโs sweeping tariffs that rattled global supply chains.Shares of other US railroad operators also rose as reports of a potential mega merger gained traction.According to sources cited by the Associated Press, Union Pacific and Norfolk Southern are in talks for a tie-up that would create a transcontinental railroad connecting the East and West Coasts. The negotiations reportedly began earlier this year, but neither company has officially commented.If the deal materialises, it would combine the largest and smallest of the major US railroadsโa move that would face significant regulatory scrutiny. The Surface Transportation Board (STB), which oversees US rail mergers, has maintained a high bar for consolidation in the sector since past tie-ups caused major operational disruptions.Union Pacificโs own 1996 merger with Southern Pacific led to prolonged rail congestion in the West. Similarly, the 1999 carve-up of Conrail between Norfolk Southern and CSX caused gridlocks in the East.Still, in 2023 the STB approved the $31 billion merger of Canadian Pacific and Kansas City Southern, creating CPKCโthe first major North American rail merger in over two decades. That deal, however, involved the two smallest Class I railroads and was not subject to the stringent post-2001 merger rules due to Kansas City Southernโs exemption.For any major consolidation under current regulations, the companies must prove that the merger would enhance competition and serve the broader public interest.As speculation around the Union Pacific-Norfolk Southern deal continues, market watchers say regulatory hurdles remain highโthough strong earnings and the potential for cross-country connectivity are fueling investor optimism.