Union Pacific long rail delivery opens Pueblo mill

Union Pacific long rail supply has entered a new phase after Rocky Mountain Steel Mills delivered the first product from its newly opened Pueblo production line.

New Pueblo mill begins long-rail production

The delivery marked the official start of operations⁠ at the $1.2 billion facility in Pueblo, Colorado. Its production line makes 100-meter (328-foot) premium rails, more than four times the length of a standard 80-foot rail. According to the companies, the longer product requires 80% fewer welds and improves track safety and reliability. 

Union Pacific CEO Jim Vena toured the plant and met employees during the handover. Rocky Mountain Steel Mills is the only remaining dedicated rail-production facility in the United States, while steel supplied to Union Pacific and its other customers is produced by United Steelworkers members.

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Doug Matthews, CEO of parent company Orion Steel, said:

“This mill is an essential part of America’s steel transportation infrastructure. Its continued existence shows that our nation offers railroads large and small the very best product, made by the very best steelmakers in the world.”

The wider Pueblo site has annual capacity of 1.1 million tons of electric-arc-furnace steel. Rocky Mountain Steel says this process produces 75% fewer carbon dioxide emissions than traditional blast furnaces, while 750,000 solar panels can provide up to 95% of the mill’s electricity. 

Seven-year contract renews a historic supply link

Union Pacific and Rocky Mountain Steel signed a seven-year domestic rail-production contract⁠ in April 2026. The agreement supports the railroad’s plan to purchase most of its rail from the Colorado manufacturer and follows the mill’s transition to new ownership and management. 

The relationship dates to the 19th century. Union Pacific bought the first rail produced by the original Pueblo mill in 1882 and has used rail from the site since the early 1890s. 

Vena said:

“Union Pacific and Rocky Mountain Steel Mills have a proud history of supporting American manufacturing, jobs and communities. As we look to the future, this renewed partnership will help strengthen our country’s supply chain and demonstrates the importance of reliable rail transportation in keeping our economy moving.”

Beyond premium rail, the facility produces wire rod, rebar and seamless tubular goods for infrastructure, construction, telecommunications, automotive, oil, gas and geothermal applications.

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