The agency's full board voted in favor of using money from its contingency fund that would allow contractors to work additional and longer shifts in order to complete work, like installing escalators and elevators, and finishing facility power and electrical distribution rooms at each station.
Contractors must finish by set milestones, which are still to be determined, or they won't receive that milestone's payment, officials say.
By tapping into back-up funds, the Second Avenue Subway would be able to start preliminary running for pre-revenue testing and training by Sept. 1 and would begin full service in December, according to MTA Capital Construction, which oversees the project.
If the subway line were not to be completed by December 2016, it would not be done until sometime in 2017 and would "have a financial impact on construction and support costs as well as the operating budget and prolong crowded conditions on the Lexington Avenue line," according to the MTACC officials.
After taking out $66 million from the MTA's contingency fund, there would be $50 million left, which would be enough if any unforeseen costs come up, according to Michael Horodniceanu, the MTACC's president.
The MTA's Transit and Bus Committee approved the proposal on Monday and its full board unanimously approved it on Wednesday.
Construction of the $4.5 billion Second Avenue Subway project began in 2007 with the goal of connecting the Q line to the Lexington/63rd Street station, and provide service from East 63rd to East 96th streets along Second Avenue.