was completed in 2000. In addition, power infrastructure had to be upgraded to allow the construction of MetroCard vending machine equipment. In 2002, the Broadway Line station was upgraded for ADA-accessibility and its original late 1910s tiling was restored. As part of the upgrade, the MTA repaired the staircases, re-tiled for the walls and floors, upgraded the station's lights and the public address system, installed yellow safety treads along the platform edge, new signs, and new trackbeds in both directions. As part of the 2015–2019 MTA Capital Program and the L Project, several modifications were implemented on the platform to improve circulation and to reduce crowding. The stairs from the Broadway Line platforms were rebuilt in March 2019; the stair from the downtown Broadway Line platform was reconfigured entirely. Additionally, a new escalator was installed from the east mezzanine to the platform; it cost around $15 million and opened on September 10, 2020. Station layout The IRT Lexington Avenue Line and BMT Broadway Line stations run roughly parallel to each other in a north–south direction. The Lexington Avenue Line platforms run under Fourth Avenue and Union Square East, while the Broadway Line platforms to the west run under Broadway, cutting directly under Union Square Park. The BMT Canarsie Line station runs west–east under both of the other stations, along 14th Street. A mezzanine stretches above the BMT Broadway Line platforms, ramping down to a control area at its south end, where there are stairs down to the Broadway Line platforms and transfers to the other platforms. Along the mezzanine and adjacent passageways, the tops of the walls contain friezes made of raised geometric patterns on the rectangular tiles. White-on-green tiles with the number "14" are placed at the tops of the walls at regular intervals, while white-on-green "Union Square" tablets are installed below the friezes. Rectangular red metal frames also surround sections of the original wall. The mezzanine is relatively shallow, and because it was built with insufficient clearance, Union Square Park was raised by to accommodate the station. Imprinted on the walls are over 3,000 stickers with the names of victims of the September 11 attacks, which were put up by artist John Lin and sixteen friends on September 10, 2002. The stickers were not sanctioned by the subway system's operator, the Metropolitan Transportation Authority, and have deteriorated since they were placed. Directly east of the control area at