Rocky Mountain Steel Mills Delivers First 328-Foot Rail

PUEBLO, COLO. – On July 17, 2026, Rocky Mountain Steel Mills (RMSM) dispatched the first stick of 328-foot-long rail from its newly completed Pueblo facility to Union Pacific Railroad, formally starting operations at the $1.2 billion plant and initiating a seven-year supply contract. The mill, owned by Orion Steel, is the first solar-powered steel mill in the world and the sole remaining U.S. producer of railroad rail.

What Is the Full Scope of This Project?

The Pueblo facility is the world’s first solar-powered steel mill and the only dedicated rail producer in the United States. The 328-foot (100-meter) rails are approximately four times longer than standard 80-foot sections, cutting the required field welds by 80% and improving track safety and reliability for Union Pacific and its customers. An on-site solar farm spanning 1,800 acres with 750,000 panels supplies up to 95% of the mill’s electricity, according to RMSM. The $1.2 billion investment covers the entire production line, from steelmaking to finishing, and replaces older capacity that had been the source of a supply dispute with Union Pacific until a settlement was reached in 2025 (Source: Manufacturing Dive, 2025). Annual production capacity in tons has not been publicly disclosed.

Key Project Data

How Does This Compare to Similar Projects?

Comparable greenfield rail mill investments are rare in North America. The only recent domestic steel project of comparable scale is the ongoing $1.2 billion modernization of U.S. Steel’s Mon Valley Works, though that focuses on flat-rolled products for automotive and appliance markets, not rail (Source: U.S. Steel, 2021). In Europe, Třinecké železárny, the Czech Republic’s sole rail manufacturer, produced 2.42 million tonnes of steel in 2025, exporting 90% of its rail output, but its facilities are not solar-powered (Source: GMK Center, 2026). The broader railway system market is projected to reach $32.5 billion in 2026, with the rail segment growing at a 5.6% CAGR through 2035, underlining the strategic value of domestic long rail production for North American freight corridors (Source: Future Market Insights, 2025).

Editor’s Analysis

The Pueblo mill’s launch reshapes the U.S. rail supply chain by consolidating all domestic production under a single, state-of-the-art roof and locking in Union Pacific’s prime supplier for the next seven years. While the solar-powered design aligns with the industry’s decarbonization push—highlighted by the 4.4% CAGR in railway system investment through 2026—the concentration of critical rail output in one location introduces a single-point-of-failure risk that freight railroads will need to monitor. This project also reflects a broader pattern: infrastructure renewal and supply chain sovereignty are driving capital into heavy manufacturing, a trend that Future Market Insights projects will push the global railroad market from $330 billion in 2025 to $569 billion by 2035.

FAQ

Q: How long are the new rails and why does length matter?
A: Each stick is 328 feet (about 100 meters), roughly four times the standard 80-foot rail. The extra length reduces the number of welds in a mile of track by 80%, which lowers maintenance costs and improves ride quality and safety.

Q: What is the annual production capacity of the Pueblo mill?
A: Rocky Mountain Steel Mills has not publicly disclosed the mill’s annual tonnage capacity.

Q: Is the mill entirely powered by solar energy?
A: The on-site 1,800-acre solar farm, with 750,000 panels, provides up to 95% of the facility’s electricity, making it the world’s first and largest solar-powered steel mill.

Q: Who owns Rocky Mountain Steel Mills?
A: RMSM is a subsidiary of Orion Steel, whose CEO is Doug Matthews.