New York City Subway is the biggest underground system in the world by the number of stations and seven by the passenger flow.
The system appeared in 1868 when overground trunk-railway with a cable traction was opened. It was changed on a steam traction in 1871 and in 1890 on electric.
Total length of exploited railways is 1355 km. There are 1056 km used for a passengers transportation.
An underground system of New York comprising 4 of 5 districts.
An official number of stations — 469.