as an underground entrance directly from One Vanderbilt to the 42nd Street Shuttle platforms. Three new staircases from the mezzanine to the southbound Lexington Avenue Line platform, and one new staircase to the northbound platform, were added. The project also involved reconfiguration of columns supporting the nearby Grand Hyatt New York hotel at the southeast corner of the station, destruction of 40% of the Hyatt's basement to expand the subway mezzanine, and the thinning of columns on platforms and mezzanines to increase space. A new elevator was added within the existing Hyatt entrance, and the existing staircase was replaced. This would directly result in additional capacity for the station, since 4,000 to 6,000 more subway passengers per hour would be able to use it. These improvements would cost over $200 million. The MTA mandated the station improvements in exchange for allowing the tower's construction. In 2015, SL Green gave $220 million toward the building's construction, of which two-thirds of the money would be used for station redesign; this marked the largest private investment to date to the New York City Subway system. The subway entrance in One Vanderbilt, as well as some of the other station upgrades, were completed in 2020. As part of the 2015–2019 MTA Capital Program, the 42nd Street Shuttle became ADA accessible, the center track was removed, and the trains became six cars long. Although the Grand Central shuttle platforms were served by elevators, the shuttle as a whole was inaccessible because the platforms at Times Square were not accessible. The whole project will cost $235.41 million, while the cost of this part of the project is $30 million. At Grand Central, the center track, track 3, was removed and the two existing platforms were connected, providing one wide island platform with an area of . This became the largest platform in the subway system. The existing platforms were extended further west to accommodate six-car trains, using existing employee facility rooms. New consolidated employee facility rooms were constructed at the location of the switch connecting tracks 1 and 3. The P-4 staircase at the western end of the station leading to Madison Avenue from the existing northern platform was removed and the P-3 staircase leading there from the existing southern platform was considerably widened. By December 2016, the project was delayed, with construction set to start in December 2019 and be completed by September 2022. A