STB Final Environmental Assessment for Mesa Rail Line

STB Press Releases

Published February 27th, 2026

Detected March 14th, 2026

Summary

The Surface Transportation Board (STB) has issued a Final Environmental Assessment (Final EA) for Union Pacific Railroad Company's proposed new rail line in Mesa, Arizona. This completes the STB's environmental review for the project.

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What changed

The Surface Transportation Board's Office of Environmental Analysis (OEA) has issued a Final Environmental Assessment (Final EA) for Union Pacific Railroad Company's proposed construction of approximately six miles of new rail line in Mesa, Arizona. This document responds to comments on the Draft EA and provides final recommendations for mitigation measures, completing the Board's environmental review. The Board will now consider the transportation merits and the environmental record in its final decision.

This issuance marks the completion of the environmental review phase. While the Final EA itself does not impose new obligations on regulated entities, it is a critical component of the STB's decision-making process for the Union Pacific project. The Board's final decision on the merits of the rail line construction will follow.

Source document (simplified)

Home » News & Communications » Latest News » STB Issues Final Environmental Assessment for Proposed New Rail Line in Mesa, Arizona

STB Issues Final Environmental Assessment for Proposed New Rail Line in Mesa, Arizona

For Release
02/27/2026 (Friday)
No. 26-05
[PDF Version]

Contact:

(202) 245-0245

The Surface Transportation Board’s Office of Environmental Analysis (OEA) today issued a Final Environmental Assessment (Final EA) for the proposed construction of approximately six miles of new rail line in Mesa, Arizona by Union Pacific Railroad Company (UP). The proposed line would connect UP’s Phoenix Subdivision main line to industrial properties southeast of the Mesa Gateway Airport.

The Final EA responds to comments received on the Draft EA and sets forth OEA’s final recommendations, including final recommended mitigation measures, to the Board. Issuance of the Final EA completes the Board’s environmental review for this project. The Board will now consider the transportation merits and the entire environmental and historic record, including the Draft EA, Final EA, and all comments received as part of its final decision.

The Final EA in Union Pacific Railroad Company—Construction and Operation Exemption—in Maricopa County, Ariz., Docket No. FD 36501, may be viewed and downloaded from the following links: Final EA, Appendices.