Manhattan's largest real estate developer has agreed to invest $220 million in renovations for Grand Central Terminal in exchange for special zoning to accommodate its planned 63-story office tower
"This is something we would have not been able to do with public funds, given all of the demands on the MTA and all of the demands on the city, but something we could do through the right kind of development," de Blasio told the crowd.
SL Green detailed that two thirds of the $220 million—the largest private investment in MTA infrastructure in the city's history—will go towards alleviating overcrowding at Grand Central.
In addition to new stairwells at both ends of the two 4/5/6 platforms, AM New York reports that the developer will also bulldoze the Hyatt Hotel basement that currently cuts into the subway, increasing mezzanine space by 40%. SL Green will also construct two new street-level subway entrances, and increase platform space by removing bulky columns that currently support the Hyatt in favor of a narrower design.

(via SL Green)
The city says that the renovations will make room for 2,200 more riders every hour at the station, and that the MTA will provide one additional train per hour in each direction to accommodate them. Grand Central currently accommodates about 154,000 per workday.
There are also plans for a new 14,000-square-foot pedestrian plaza on Vanderbilt Avenue in the shadow of One Vanderbilt, which will take up the block between Vanderbilt and Madison Avenues and 42nd and 43rd Streets.
A new concourse under One Vanderbilt will eventually connect Grand Central commuters to the $10 billion, perennially delayed East Side Access project, which will connect Long Island Rail Road trains to Grand Central. Most recently targeted for a Christmas 2022 completion, East Side Access was delayed again over the summer amid a dispute between MTA and Amtrak regarding nights and weekends construction.
MTA spokesman Kevin Ortiz declined to comment on how the project might impact the East Side Access timeline, instead directing us to a statement from MTA Chairman Tom Prendergast. "The MTA will continue to support innovative proposals that link development with transit investment, and we hope that One Vanderbilt is the first of many to come," the chairman said.
The Grand Central renovations will be completed in 2020, according to the Mayor's office.

(via SL Green).
"It's understandable that there's a certain skepticism when New Yorkers hear promises about what development will do for them," de Blasio said on Tuesday.
When the Barclays Center opened in Brooklyn in 2012, none of the promised 2,000 affordable apartments had been constructed (the project's first affordable housing lottery launched this past April). To appease the skeptics, SL Green has agreed to keep its most expensive upper-floor offices off the market until the ribbon cutting on the transit upgrades.
"Tenants cannot move into the upper floors of this building until this infrastructure is done that the people need," de Blasio said.
"I think it's a strong agreement that the city made," said Riders Alliance spokesman John Raskin on Tuesday. "Untangling these crowded subway stations is a difficult task, but these improvements are significant and meaningful."
"Midtown Manhattan is an appropriate place for high-density development," he added, comparing Midtown East to neighborhoods like Downtown Brooklyn, where advocates have protested large-scale development without accompanying public transit investment.
The city's 78-block Greater East Midtown rezoning proposal includes the area surrounding Grand Central, and is likely to go up for public review before the end of the year. Manhattan Borough President Gale Brewer called today's groundbreaking "a first step toward the future of East Midtown."
"The area around Grand Central, to the east, is going to redevelop at some point anyway," predicted Bill Henderson, director of the MTA watchdog group Permanent Citizens Advisory Committee to the MTA. "I'd rather have more people come into the area with some transit improvements."
He added that while the project likely won't speed up East Side Access, it could "really do some good," by making 4/6/5 platforms less congested, and allowing trains to run on schedule. Under the current circumstances, it's not uncommon for large crowds to queue around car doors, stalling trains in the station and reverberating delays along the line.
"An extra train per hour will be great," Henderson said. "But the first step is getting on schedule."
Correction: An earlier version of this piece incorrectly stated that SL Green is using Grand Central's air rights in constructing One Vanderbilt. In fact, a lawsuit over those air rights was settled over the summer, without those rights being transferred. The details of the settlement were not disclosed at the time; a spokeswoman for the mayor's office said that the tower can proceed thanks to a "special permit granted by City."