three stations part of the contract, Wall Street and Fulton Street, while work at Bowling Green was already completed. The entire platform-lengthening project was substantially completed by November 1965. Because the Lexington Avenue Line during the 1970s was known to frequent muggers due to the dilapidated state of the subway at the time, the Guardian Angels, founded by Curtis Sliwa, began operations on February 13, 1979 by conducting unarmed night patrols on the 4 train in an effort to discourage crime. These patrols later expanded to other parts of the subway and to other city neighborhoods. On August 28, 1991, an accident involving a 4 train on the express track just north of the 14th Street–Union Square station killed five riders and injured 215 others in the worst accident on the system since the 1928 Times Square derailment. As a result of the crash, new safety protocols were put in place and there was a partial implementation of automation of the New York City Subway. Overcrowding The Second Avenue Elevated fully closed on June 13, 1942. Because of the elevated line's closure, as well as a corresponding increase in the East Side population, crowding on the Lexington Avenue Line increased. The Manhattan section of the Third Avenue Elevated, the only other elevated line in the area, closed on May 13, 1955, and was demolished in 1956. Contrary to what many East Side residents thought, the demolition of the elevateds did not help the travel situation, as the Lexington Avenue Line was now the only subway transportation option on the East Side. As the elevated lines were torn down, hundreds of high-rise apartment buildings were built on the East Side, and the business districts along the line grew, resulting in overcrowding along the line. Both of these elevated lines were supposed to be replaced by a subway line under Second Avenue. However, it was not completed due to a lack of funds. With the city's economic and budgetary recovery in the 1990s, there was a revival of efforts to complete construction of the Second Avenue Subway. Once fully built, the line will run from 125th Street and Lexington Avenue to Hanover Square in the Financial District. Construction started in 2007, and on January 1, 2017, the first phase, between Lexington Avenue–63rd Street and 96th Street opened. Within a few months of the line's opening, crowding on the Lexington Avenue Line stations