6d (New York City Subway service) in the context of "Parkchester, Bronx"

599 Lexington Avenue is a 653-foot (199 m) tall, 50-story skyscraper in Midtown Manhattan, New York City, designed by Edward Larrabee Barnes/John MY Lee Architects. It was the first building constructed by Mortimer Zuckerman and his company Boston Properties in New York City. The site was acquired for $84 million in 1984, and completed in 1986. The building is adjacent to the Citigroup Center and is considered a well-designed contextual partner to the area.

It is tied with both of the Silver Towers as the 104th tallest building in New York City. The lobby contains Frank Stella's Salto nel Mio Sacco. The property also contains an entry to the Lexington Avenue/51st Street station of the New York City Subway, served by the 6, <6>​​, E, and ​M trains. The entryway to the station features a sloped glass canopy. The building was completed without an anchor tenant.

The Grand Central–42nd Street station (also signed as 42nd Street–Grand Central) is a major station complex of the New York City Subway. Located in Midtown Manhattan at 42nd Street between Madison and Lexington Avenues, it serves trains on the IRT Lexington Avenue Line, the IRT Flushing Line and the 42nd Street Shuttle. The complex is served by the 4, 6, and 7 trains at all times; the 5 and 42nd Street Shuttle (S) trains at all times except late nights; the <6> train during weekdays in the peak direction; and the <7> train during rush hours and early evenings in the peak direction.

The station is adjacent to Grand Central Terminal and Grand Central Madison, which serves all Metro-North Railroad lines east of the Hudson River and Long Island Rail Road lines east bound for another major hub Jamaica and several points east. There are multiple exits to Grand Central Terminal and to nearby buildings such as One Vanderbilt and the Chrysler Building. Numerous elevators make the station compliant with the Americans with Disabilities Act of 1990.

The IRT Lexington Avenue Line (also known as the IRT East Side Line and the IRT Lexington–Fourth Avenue Line) is one of the lines of the A Division of the New York City Subway, stretching from Lower Manhattan north to 125th Street in East Harlem. The line is served by the 4, ​5, ​6, and <6> trains.

The line was constructed in two main portions by the Interborough Rapid Transit Company (IRT), a private operator. The first portion, from City Hall north to 42nd Street, was opened between 1904 and 1908, and is part of the first subway line in the city. The original subway turned west across 42nd Street at the Grand Central station, then went north at Broadway, serving the present-day IRT Broadway–Seventh Avenue Line. The second portion of the line, north of 42nd Street, was constructed as part of the Dual Contracts, which were signed between the IRT; the Brooklyn Rapid Transit Company, via a subsidiary; and the City of New York.

The Lexington Avenue/51st Street station is a New York City Subway station complex on the IRT Lexington Avenue Line and IND Queens Boulevard Line. The station is located on Lexington Avenue and stretches from 51st Street to 53rd Street in Midtown Manhattan. It is served by the 6 and E trains at all times; the F train on weekdays during the day; the <6> train during weekdays in the peak direction; the <F> train during rush hours in the reverse peak direction; and the 4 train during late nights.

The complex comprises two stations: 51st Street on the Lexington Avenue Line and Lexington Avenue–53rd Street (originally Lexington–Third Avenues) on the Queens Boulevard Line. Originally two separate stations, these were connected in 1988 via a transfer passage, which was opened with the construction of 599 Lexington Avenue. Approximately 50,000 riders transfer between the Lexington Avenue and Queens Boulevard Lines each weekday.