(The part of BART that extends through the Peninsula runs aboveground from Daly City to Millbrae. For that matter, the part of BART that runs through the East Bay goes along the former Western Pacific right-of-way, aboveground. And the Transbay Tube was constructed with the "immersed tube" technique, built on land, towed out to sea, and submerged. Where BART runs underground and was built with TBMs, it's usually in bedrock under the cities of SF and Oakland.)
nostrademons|10 months ago
(The part of BART that extends through the Peninsula runs aboveground from Daly City to Millbrae. For that matter, the part of BART that runs through the East Bay goes along the former Western Pacific right-of-way, aboveground. And the Transbay Tube was constructed with the "immersed tube" technique, built on land, towed out to sea, and submerged. Where BART runs underground and was built with TBMs, it's usually in bedrock under the cities of SF and Oakland.)