The 200-ton drill will remain 14 stories below the surface of the earth.
"A recent visit to the cutter's future crypt revealed a machine that evokes an alien life form that crashed to earth a millennia ago. Its steel gears, bolts and pistons, already oxidizing, appeared lifeless and fatigued. A wormlike fan, its exhaust pipe disappearing into the cutter's maw, was still spinning, its drone not unlike a slumbering creature's breath.
"If you came and visited this 100 years from today, this is what you'd see," said Dr. Horodniceanu, balancing on a catwalk that overlooks the enormous contraption. "People would not know what it's all about."
The cutter head, known as Seli after its Italian manufacturer, has been eating its way through several miles of Manhattan schist since 2007. Its flat face is equipped with 45 rotating discs, each carrying a layer of tungsten carbide, an exceptionally strong alloy that can easily break through the city's bedrock. (Rumors that the machine used diamonds for this purpose were "an urban legend," according to a transportation authority spokesman.)"