The first $4.451 billion dollar phase of the 2nd Avenue Subway, from 96th Street down to 63rd Street, is 82 percent complete, according to the MTA's Capital Construction president Michael Horodniceanu, who is fairly confident the the line will open in December 2016 as expected—barring any unforeseen complications. A tour underground yesterday showed the project is well on its way, with those scary mud caverns slowly but surely transforming into scary subway tunnels.

So far, the MTA has finished boring and excavating the tunnels; they've begun installing tracks, and have been working on completing the new stations at 96th and 86th Street, along with a massive, 1,400-foot-long station at 72nd Street. The 63rd Street platform, which is almost finished, is housed inside the Lexington-63rd Street F station, which is currently under construction and will gain four new entrances by the project's completion.

Some other fun facts: the new stations will all be "air-tempered," which means platform temperatures will be kept 10 degrees cooler than outside in warm weather. The new trains will not initially be run using the Communications-Based Train Control (CBTC) system, but the MTA plans to upgrade them eventually. There will be no stair-access at the 72nd Street station, with one entrance boasting five elevators and the other two accessible via escalator only.

The 72nd Street station will also be one of the top three deepest stations in the city; all stations will be cavernous, akin to the Washington, DC metro system, and the columns that dot all the current stations are a thing of the past.

The project's most difficult task will be testing and integrating the new trains with the system that's already in place. "Every time you take something old and add something new, it's unique," Horodniceanu told us. "We're not building something from scratch here.

And according to Horodniceanu, rats have yet to claim the new subway's tracks for their own, though that could change when hungry humans start descending into the tunnels. "Don't bring food in here," he told us. "Rats do not like concrete and rubber. They like food."

As for that $4.451 billion price tag, Horodniceanu says the project's stayed within budget so far. Still, "unless something extraordinary happens," the agency doesn't have the money to schedule, start and complete Phases 2, 3, and 4, a predicament MTA chairman Tom Prendergast floated back in March. The MTA included $1.5 billion for the second phase in its proposed 2015 Capital Plan, but Albany has thus far left the agency severely underfunded.

Which is a shame, because the full Second Ave Subway is expected to alleviate one of, if not the most congested lines in the system—the 4,5,6 trains carry 1.6 million people per weekday, and as anyone who's stood near that platform at Union Square can tell you, a commute on that line is not always pleasant. If and when all four phases are completed, the new line will run from 125th Street all the way down to Hanover Square with connections to the Q,4,5,6,B,D and F lines.