Seattle Tube Blog

Location at south end of the TUBE on Sixth Ave East of Quest Field looking north under the I-90 access overpass.

North end of the TUBE on Sixth Ave at the entrance of the Battery Street Tunnel.


A Better Place to Dig...

Due to the recent big building projects downtown with their deep foundations, more is known about the ground under the city than near the water's edge. In 1903, a railroad tunnel was dug under the city to alleviate traffic congestion along the waterfront - in those days it was done all by hand. What little is known is that much of the waterfront is soft fill consisting of sawdust from the old Yesler Sawmill, ship ballast, and debris left over from the Seattle Fire of 1889. - All dumped over the soft muddy harbor bottom that is now Alaska Way. These variables are sure to cause hefty cost overruns if they build either a bigger viaduct or tunnel along the shore.

Up around Sixth avenue is a better place to dig. The ground is solid, and the nature of the soil is a known commodity (An important issue for accurate construction bidding). But the real advantage is that both tunnel entrances are in areas that are not primary traffic zones. Construction can be done without affecting the already strained Seattle commute on SR99 until its time to switch over.

The current waterfront tunnel option touted by supporters features a steep grade to transition between the elevation of the Battery Street Tunnel and below sea level. This will most likely frustrate commuters, as heavy trucks will hold back traffic while ascending the northbound hill. The Tube can be built with much less of a critical grade, enabling smoother traffic flow.


Looking south on sixth near Bell Street. There is ample room to work on the north entrance to the Seattle Tube bellow 6th Avenue.


Looking north on Sixth and Battery Street where the TUBE could intersect with the existing Battery Street Tunnel to provide access to and from Western Avenue.


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