are counted, the New York City Subway has the largest number of rapid transit stations in the world. There are numerous New York City Subway stations that are closed, many of which stem from the demolition of elevated lines once operated by the IRT and the BMT that were made largely but not completely redundant to underground lines subsequently constructed. The newest New York City Subway stations are part of the Second Avenue Subway, and are located on Second Avenue at 72nd, 86th and 96th streets. They opened on January 1, 2017. Stations that share identical street names are disambiguated by the line name and/or the cross street each is associated with. For example, "125th Street station" can refer to four separate stations: 125th Street on the IND Eighth Avenue Line (), the IRT Broadway–Seventh Avenue Line (), the IRT Lenox Avenue Line (), and the IRT Lexington Avenue Line (). This situation occurs numerous times. Station facilities and amenities Of the stations in the system, are served 24 hours a day. Underground stations in the New York City Subway are typically accessed by staircases going down from street level. Many of these staircases are painted in a common shade of green, with slight or significant variations in design. Other stations have unique entrances reflective of their location or date of construction. Several station entrance stairs, for example, are integrated into adjacent buildings. Nearly all station entrances feature color-coded globe or square lamps signifying their status as an entrance (see below). Out of all the stations on the New York City Subway, 275 are fully underground (59%) 153 are elevated stations (32%) 29 are on an embankment (6%) 15 are open-cut stations (3%) This means that 61% of the stations are below the surface (59% being fully underground and about 2% with most of the station below the surface). 39% of stations are above the surface or overground. Entrances Turnstiles and entrance gates The New York City Subway primarily employs two types of turnstiles: a waist-high turnstile, and a full-height turnstile known as a High Entry-Exit Turnstile (HEET). The waist-high turnstiles, the most prominent in the system, were installed beginning in 1993 along with the implementation of MetroCard, though they originally accepted tokens. The newer HEETs resemble several older turnstiles of that design informally called "iron maidens", and are prevalent at subway entrances without token booths to discourage fare evasion.