Far below street level, carved out of the dense metamorphic bedrock known as Manhattan schist, the city's newest subway line is taking shape.

The tracks are laid on low-vibration pads, which are made of rubber and neoprene and encased in concrete. In the above photo, the third rail has yet to be installed on the left.

"This is the third deepest station that we have in the system," says the president of MTA capital construction, Michael Horodniceanu. "The lower level is 134 feet down."

MTA Capital Construction President Michael Horodniceanu, displaying the granite to be used on the floors of the Second Avenue subway stations. The walls will have porcelain tile, which officials say is easier to keep clean.

(Kate Hinds )

The tunneling work from 63rd to 96th streets is done. The three new stations are large and cavernous, like Washington  D.C. Metro stations. They lack columns. They have mezzanine levels. And when you stand on the platform and look  through the tunnels, they look like giant owl eyes.  

Horodniceanu said children often come to the Second Avenue Subway's Community Information Center and ask questions. Staff kept trying to explain the size of the project to them, but the kids were struggling to visualize it . "So one of the guys here figured out how many elephants could fit in the (72nd Street) cavern," he said, "and the children then got it."

How many elephants would fit? "Fifty-five thousand."

The stations along the Second Avenue line are more open than typical subway stations — and there won't be the usual support pillars on platforms. (Kate Hinds )

A rendering of the Second Avenue subway's column-free stations

(Kate Hinds )

The project is now 82 percent complete. Now, says Horodniceanu, comes the hard part.

"I'm not going to kid myself," he said. "This is the toughest 18 percent, because these are the finishes and the systems."

A signal relay room. Although the signals are new, the technology is compatible with the same signals that have been used in the subway for decades.

(Kate Hinds)

Equipment in the signal relay room

(Kate Hinds )

Under wraps: a piece of the Second Avenue subway's signal relay control equipment

(Kate Hinds )

Fire control and ventilation systems have to be rigorously  tested. The new signal relay rooms have to be wired perfectly in order to communicate with MTA's control rooms elsewhere in the system.

It's an especially delicate job, because the original subway system is over 110 years old.

Cooling systems will keep the platforms about 10 degrees cooler than the outside

(Kate Hinds)

"We have to marry brand new technology with technology that may not be exactly at the same pace," says Horodniceanu.

The Second Avenue Subway

(Kate Hinds)

When asked how confident he is that the line would open by next December, Horodniceanu ballparked it at 75 to 80 percent.

This shaft is large enough to house five different elevators.

(Kate Hinds )

But an electrical worker who gave his name as Brian was much more confident.

A future station booth on the mezzanine at 86th Street. The MTA says the new line were serve approximately 200,000 daily riders.

(Kate Hinds )

"I'm not worried. I'm not worried," Brian said. "We'll get it done. We always come through."

A worker in a Second Avenue Subway tunnel

(Kate Hinds )

The Second Avenue Subway will connect to the F at 63rd Street and run to 72nd, 86th and 96th Street as the Q. Officials say this font was just a test and will be replaced with something more in line with the rest of the subway system.

(Kate Hinds )

The northbound tunnel, awaiting track installation.

(Kate Hinds )

A Second Avenue Subway tunnel

(Photo: Marc A. Hermann / MTA New York City Transit)

An entrance at a future Second Avenue Subway station

(Marc A. Hermann / MTA New York City Transit)

The Second Avenue subway will run as an extension of the Q train -- it won't formally become the T until the line goes further south

(Kate Hinds )