Twin tunnel boring machines will begin by tunneling parallel underground sections between the future Wilshire/La Brea Station and the current Wilshire/Western Purple Line terminus.
Angeli, the tunnel boring machine, was lowered into the ground near 1st and Central in late 2016 and began digging the tunnels in early February.
At the event Board Chair Fasana awarded TAP Cards to students who won contests to name the TBM and create an illustration for its tail shield.
Two TBMs excavated and constructed the Central Subway’s 1.5 mile-long tunnels at an average pace of 40 feet per day and will be retrieved in North Beach at the site of the former Pagoda Palace Theatre on Powell Street.
Beginning Tuesday, Big Alma was set to be in operation 24 hours a day to build the approximately 425 feet of new tunnel beneath the Market Street tunnels.
In the coming months, the two machines will travel north under 4th Street, Stockton Street and Columbus Avenue, excavating and constructing San Francisco’s first new subway line in decades.
The new tunnels represent one complete section of the twin tunnels that will connect the future Sheppard West and Finch West Stations. The tunnel boring machines named "Holey" and "Moley" bored the tunnels.
The 21-foot diameter tunnel boring machine emerged within three millimeters of its target as part of the University Link light rail expansion.