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Holethrough Part II — Second tunnel boring machine scheduled to bust through on Broadway

The first Broadway holethrough (Image: Sound Transit)

Sound Transit says the second of two massive tunnel boring machines has made its way from Montlake to Capitol Hill and will “holethrough” the northern wall of the light rail station construction site Monday afternoon. 

CHS covered the arrival of the first machine on March 21st after a 10-month journey from the University of Washington stadium parking lot where it began its trek as part of the $1.9 billion, 3-mile line connecting downtown to Montlake via Capitol Hill.


Franklin Tseng, owner of the Capitol Building near the station, said he remains concerned about the giant machines passing so closely below the 1924 structure.

“We have been approaching Sound Transit to take ultimate precautions in the drilling operation,” Tseng tells CHS via email. “Will see when the 2nd one pass through. It is a long term problem and let’s hope that the soil underneath will hold up.”

Sound Transit representative tell us there appear to have been no issues with the building since the arrival of the first TBM last month saying there “haven’t been any issues at all with the monitoring at the Capitol Building.”

Meanwhile, some residents above the twin tunnels connecting Capitol Hill to Montlake continue to report vibrations and noise associated with underground work in the area. Check out the CHS comments for some of the reports from neighbors and concerns about the possibility the vibrations could continue when the light rail line begins operations in 2016.

The end of the boring between Montlake and the Hill won’t end of tunneling work in the area. Sound Transit contractors still need to complete dozens of 15 cross-passages to connect the tunnel routes at various points along the two-mile line. A third tunnel boring machine is also about to complete its second tour of duty completing the twin tunnels between Broadway and downtown.

Here’s video of the first holethrough. We’re assuming the second break-through will look the same — only sunnier:

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One thought on “Holethrough Part II — Second tunnel boring machine scheduled to bust through on Broadway

  1. Congrats to CHS for getting a photo posted before Sound Transit. I looked all over their site for additional info on the breakthrough, but found none. That’s one reason why I come here to get my local news. Well done.