[11][12] Originally, the commission had assigned the operation of the Lexington Avenue Line in Manhattan to the BRT, as the IRT had withdrawn from negotiations over the proposed tri-borough system.

[26] IRT subsidiary Rapid Transit Subway Construction Company received a $1,915,164 contract to build section 7 the next month.

[27][28] The Public Service Commission received the rights in July 1915 to build subway entrances within the Nursery and Child's Hospital at the southeastern corner of Lexington Avenue and 51st Street, which would have served the IRT station there.

The Metropolitan Transportation Authority (MTA) intended to provide matching funds for the project,[56][57] but it had not approved a contract for the renovation by early 1970.

[58] In July 1968, MTA subsidiary New York City Transit Authority (NYCTA) completed plans to construct a 320-foot (98 m)-long free transfer passageway between the north end of the 51st Street station and the Lexington Avenue mezzanine of the Lexington Avenue station.

[60][61] The passageway was not built at the time; passengers still had to exit to the street and pay an extra fare to transfer between the stations.

[64] The escalators at the western end of the IND station were replaced in 1977,[65] and a new subway entrance was built as part of the construction of Citicorp Center in the late 1970s.

[67] Madison Equities, the developer of an office building at 875 Third Avenue, agreed in 1981 to expand the IND station and add a retail arcade in exchange for 90,000 square feet (8,400 m2) of additional space.

[68] The New York City Planning Commission mandated that two floors of 875 Third Avenue could not be occupied unless the subway improvements were completed, or unless Madison Equities had attempted to buy out the holdout tenants.

[69] Following various legal disputes, Madison Equities finally bought out the holdout tenants in the late 1980s and completed the subway expansion.

[62] In exchange, Boston Properties would be permitted to add 146,293 square feet (13,591.1 m2) to its building,[70] expanding the structure's floor area by 20 percent.

However, the MTA's portion of the passageway was delayed by the presence of utilities, as well as the fact that workers had encountered solid rock rather than soft ground.

"[83] In April 1993, the New York State Legislature agreed to give the MTA $9.6 billion for capital improvements.

[86] Amid a funding shortfall, the MTA announced in October 1994 that it had indefinitely postponed plans for renovating the Lexington Avenue/51st Street station.

[89] In addition, reverse-peak E and F trains did not stop at the station (northbound during the morning, southbound during the afternoon) to reduce overcrowding, as only the escalators to Third Avenue remained open.

[91] The work was supposed to be completed in September 1996,[91][92] but it was pushed back by four months due to the need for asbestos abatement and the large crowds at the station.

[95] During this renovation, the transfer passageway was temporarily narrowed to as little as 6.5 feet (2.0 m) at certain points; this created hazardous conditions during rush hours.

[111]: 132 In 1976, with funding from the Exxon Corporation, this station, as well as three others citywide, received new "artfully humorous graffiti" murals and artwork.

[113] As part of the MTA Arts & Design program, an artwork by Nina Yankowitz, Tunnel Vision, was installed in the underpass connecting the IRT platforms in 1988[114] or 1989.

[115][116] The artwork consisted of blue tiles within a crack arranged in the shape of a lightning bolt, which was placed against a white-tile wall.

[115] The artwork also included a frieze atop the wall, which was patterned after the skyline of New York City, as well as decorative pilasters.

[117][118] The tiles, manufactured by Miotto Mosaic Art Studio,[119][120] depict various geometric shapes that appear to "float" along the wall, such as rings, checkerboard patterns, clouds, and pipes.

[121] The southbound Lexington Avenue Line platform has a part-time fare control area near the south end.

[128] The entrance in the General Electric Building's basement replaced the original sidewalk staircases at the southwestern corner of Lexington Avenue and 51st Street.

[121] The fare control area contains access to both the primary mezzanine, which contains the IRT transfer, as well as a set of staircases and escalators leading directly to the east end of the IND platform.

The two express tracks, used by the 4 and 5 trains during daytime hours, pass through on a lower level and are not visible from the platforms.

The station features modern beige bricks over the original tiles, but the standard IRT-style mosaics remain intact.

The platforms are approximately 25 feet (7.6 m) below street level and the station's full-time fare control areas are at the center of each.

A staircase of seven steps goes up to a turnstile bank, with a token booth and two exits to each corner on each side outside fare control.

The Lexington Avenue–53rd Street station on the IND Queens Boulevard Line opened on August 19, 1933[131][132] and has two tracks and one island platform.