Spring Speaker Series at Milepost 31

Milepost 31 celebrates the people and projects that shaped Pioneer Square and provides an inside look at the SR 99 Tunnel Project. Learn more about the project from experts in the field at the speaker series.


211 First Avenue South

Free admission

First Thursdays


May 3 – Tunneling in Seattle

A History of Innovation

Robert “Red” Robinson, Senior Vice President of Shannon & Wilson, Inc. – a Seattle-based geotechnical and environmental consulting firm

6 to 6:30 p.m.

Did you know there are more than 100 tunnels beneath Seattle? Join us for a virtual tour exploring the train, sewer, utility and transit tunnels built during the past century and learn how tunneling technology has advanced from hand tools to sophisticated boring machines.

June 7 – Meet the Tunnel Boring Machine

Replacement Program

Chris Bambridge, Tunnel Design Engineer for the Alaskan Way Viaduct

6 to 6:30 p.m.

What’s as long as a ferry, five stories tall and weighs 5,500 tons? The SR 99 tunnel boring machine! We’ll show you how this custom-designed machine will grind through rocks and remove more than 800,000 cubic tons of soil as it builds the SR 99 tunnel beneath downtown.


View full color flyer (PDF): MP31 Speaker Series