The New York City Transit Police Department , that was started in 1953 , was a transit police department for the New York City Subway and bus lines . It became part of the NYPD in 1995 as the Transit Bureau of the New York City Police Department by decision of New York City Mayor Rudolph W. Giuliani .
Discussions between the City and the New York City Transit Authority produced a memorandum of understanding , and on April 2 , 1995 , the NYC Transit Police was consolidated with the New York City Police Department to become a new Bureau within the NYPD .