The A, B, C, and D subway lines are part of the New York City Subway system, serving various neighborhoods in Manhattan, Brooklyn, and the Bronx. The A line runs from Inwood in Manhattan to Far Rockaway in Queens, providing express service along much of its route. The B line operates from Washington Heights to Brighton Beach, while the C line runs parallel to the A line, offering local service between 168th Street and World Trade Center. The D line connects Norwood in the Bronx to Coney Island in Brooklyn, making stops at key locations like Yankee Stadium and Times Square. Each line is color-coded on subway maps, with the A line in blue, B in orange, C in blue, and D in orange, helping riders navigate the extensive transit system easily.