A Metro and TriMet-led discussion about future solutions for mass transit throughout Portland led to the concept of a tunnel under the Willamette River in downtown Portland. That concept has turned into an official tunnel study as Metro and TriMet explore the “feasibility of a MAX (light rail) tunnel under downtown Portland so more people can get to all the places they want to faster.” 

The current issue revolves around the 1912-built Steel Bridge, which ties the Rose Quarter on the east side of the river to downtown core on the west side with only one train in each direction at a time. And at a slowed pace. With light rail connecting communities on both sides of the river, the busiest times of day require one train every 90 seconds and the congestion will only grow. The Steel Bridge is owned by Union Pacific Railroad and already carries more than just MAX light rail with Amtrak passenger trains and freight trains every day. 

Potential solutions include a revamped Steel Bridge, a new bridge or, as discussed now, going underground. 

“As the region grows and the demand for light rail increases, the region will need at least 64 MAX trains through downtown every hour, more than one train each minute,” says Metro. “Our current system can’t support that change.”

Metro and TriMet, then, are leading the MAX Tunnel Study in partnership with the city of Portland and Multnomah County to study the potential for a light rail tunnel from the Lloyd Center area east of the Rose Quarter to Goose Hollow in Southwest Portland. “As a first step,” Metro says, “they will determine what studies and resources they would need to bring the idea to reality.” 

The study, currently ongoing and entering a budget estimating and planning strategy stage, expects to identify opportunities and challenges with constructing a tunnel under the Willamette River and downtown Portland. 

A Metro spokesperson has called the study a feasibility exercise. The agencies hope that by September, when the study wraps, they will have a better idea of cost estimates for planning and design and potential timeline scenarios. Expectations have the tunnel cost at a minimum of $1 billion, but any project would still be years in the making, potentially sometime between 2028 to 2040. 

A twin-bore tunnel to handle transit traffic headed both east and west could include underground stations to speed service not only bypassing the Steel Bridge, but also through the more heavily congested downtown core. Skipping the Steel Bridge and downtown streets also allows for TriMet to use a longer train to carry more passengers. A tunnel solution could cut commutes 15 minutes. 

The MAX Tunnel Study isn’t the only expansion plan in the offering for TriMet, which is part of an expected 2020 multi-billion ballot measure to expand light rail throughout the region. 

Follow Tim Newcomb on Twitter at @tdnewcomb.