UP-Southern Pacific Merger Creates Largest U.S. Railroad

Over the years the Southern Pacific expanded to more than 13,000 miles of rail covering most of the southwestern United States, including the Central Pacific’s original Sacramento-to-Ogden line. On July 3, 1996, the newly formed Surface Transportation Board approved the UP-SP merger. The new system covered 31,000 miles through 24 states and ran 2,000 trains a day. With the merger, Union Pacific became the largest rail company in the United States — and saw its history come full circle as it became the owner of both halves of the first transcontinental railroad.