Denver International Airport officials plan to convert a dormant underground tunnel into pedestrian walkways, creating an alternative people-moving system so that air travelers and workers no longer have to rely on DIA’s trains for reaching concourses.

Design work will begin this year on the project to repurpose this existing baggage tunnel, adjacent to a tunnel that carries the electric trains, at an estimated cost between $300 million and $700 million, Denver Mayor Michael Johnston said. Johnston planned to announce the plans on Tuesday morning. Construction is scheduled to start next year, with the 17-foot-wide walkways opening in 2028.

DIA’s trains broke down 262 times over the past two years, airport records show. While most of the breakdowns were brief, lasting an average of four minutes, DIA officials say the lack of a backup option as the airport grows, toward a projected 120 million travelers a year by 2045, increasingly causes problems.

Repurposing the tunnel, built before the airport opened in 1995, “gives us the most affordable and fastest way to solve the challenge,” Johnston said.

https://www.denverpost.com/2026/05/2...lkways-trains/

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