Starting next year, two TBMs will build the tunnels, digging at a rate of about 40 feet per day far beneath the surface of the city. Prefabricated tunnel segments will be put in place as the TBMs advance, with a crew of about seven workers operating the machines and welding the segments together.
Each TBM consists of a rotating cutting wheel (the cutter head), a cylindrical steel shell (the shield) and a 300-foot train of tunnel-building contraptions (the tail). It takes about a year to construct this complex construction equipment.
Tunnel Boring Machine Update
Photos of the Central Subway's tunneling machines
2 Responses:
I want to see the Onion article, "TBM insists it is not boring, actually has quite exciting life".
Here's what it looks like when it finishes the tunnel.