Workers complete primary excavation of downtown Seattle transit tunnel on April 8, 1988.

  • By Walt Crowley
  • Posted 1/01/2000
  • Essay 2701

On April 8, 1988, workers complete primary excavation of a pair of 18-foot diameter tubes and five stations for the downtown Seattle transit tunnel. Work had begun on March 6, 1987, and the tunnel will open for service on September 15, 1990.

The tunnel was designed and engineered by TRA and Parsons Brinkerhoff. Construction-Pamco and Atkinson Construction/Dillingham Construction served as general contractors. Boring the primary tubes employed a pair of 140-ton mechanical moles called shield excavators.

Progress was marred by encounters with unanticipated soil conditions, one fatal construction accident (killing Alan Sandbow), and a racially charged scandal over the inadvertent use of banned South African marble that ultimately led to the resignation of Metro Director Alan Gibbs. (He was succeeded by Richard Sandaas, former Metro Transit director, who was succeeded in turn by Paul Tolliver.)

Despite these obstacles and distractions, the downtown tunnel was completed on schedule. When the tunnel opened for service on September 15, 1990, the federal Urban Mass Transit Authority hailed it as one of the most cost-effective transit project in the nation.


Walt Crowley, Routes: A Brief History of Public Transportation in Metropolitan Seattle (Seattle: Metro Transit, 1993).

Licensing: This essay is licensed under a Creative Commons license that encourages reproduction with attribution. Credit should be given to both and to the author, and sources must be included with any reproduction. Click the icon for more info. Please note that this Creative Commons license applies to text only, and not to images. For more information regarding individual photos or images, please contact the source noted in the image credit.
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License
Major Support for Provided By: The State of Washington | Patsy Bullitt Collins | Paul G. Allen Family Foundation | Museum Of History & Industry | 4Culture (King County Lodging Tax Revenue) | City of Seattle | City of Bellevue | City of Tacoma | King County | The Peach Foundation | Microsoft Corporation, Other Public and Private Sponsors and Visitors Like You