Though Sound Transit’s Tunnel Boring Maching #1 (formerly ‘Brenda’) reached UW station in September, Sound Transit only retrieved the cutter head yesterday (because football). TBM #1 has been a true workhorse for Sound Transit, completing 6 of the 10 tunnel segments for University Link and Northgate Link on its own. It also picked up the slack when TBM #2 (‘Pamela’) broke down, finishing an extra segment from UDistrict Station to UW.
Aside from a short 0.5 mile conventionally mined tunnel under construction in Downtown Bellevue for East Link, Brenda’s repose marks a ceremonial end to transit tunneling for the next decade or so. Most remaining ST2 track miles (Northgate to Lynnwood, and International District to Overlake) are at-grade or elevated, as is the bulk of the recently passed Sound Transit 3. In a country that frequently builds at-grade rail on the cheap, it’s worth reiterating how fortunate we will have been to build an 8.5 mile subway from scratch.
The next tunnels? Possibly a short tunnel from The Triangle into West Seattle Junction, and of course the mammoth undertaking of boring a new subway from Queen Anne to the International District for the Ballard-Tacoma line. If we’re lucky judicious and efficient, we’ll be christening new TBMs by the early-2020s.