The New York City Subway is a rapid transit system owned by the City of New York and leased to the New York City Transit Authority, a subsidiary agency of the Metropolitan Transportation Authority. It is the largest rapid transit system in the world by number of stations, with 468 stations in operation (421, if stations connected by transfers are counted as single stations). The New York City Subway is also one of the world's oldest public transit systems. Overall, the system contains 232 miles (373 km) of routes, translating into 656 miles (1,056 km) of revenue track; and a total of 842 miles (1,355 km) including non-revenue trackage. In 2013, the subway delivered over 1.71 billion rides, averaging approximately 5.5 million rides on weekdays, about 3.2 million rides on Saturdays, and about 2.6 million rides on Sundays. Ridership continues to increase, and on September 23, 2014, more than 6.1 million people rode the subway system, establishing a single-day ridership record.