Bertha was custom built to dig the State Route 99 tunnel under Seattle. It dug under the city (off and on) from December 2013 to April 2017.
Bertha was custom built to dig the State Route 99 tunnel under Seattle. It dug under the city (off and on) from December 2013 to April 2017.
Here’s the world’s biggest TBM.
Tuen Mun-Chek Lap Kok