722 miles

"The building of the New York City subway system was an epic struggle, and not just for engineering reasons." "As New York grew in importance throughout the nineteenth century, geography imposed physical limits on the city. Manhattan was a narrow and crowded island, with a huge population jammed into its southern tip. By the 1880s surface transportation on Manhattan streets was impossibly slow, and the city's business leadership realized that improved transportation was vital to its future. Mayor Abram S. Hewitt, a wealthy businessman, proposed a subway system, and Hewitt and other prominent businessmen established the political and financial framework for the city's first subway, which opened in 1904." "Hugely popular from its inception, the subway quickly became overcrowded. Expansion of the system was hindered by the autocratic August Belmont, a wealthy banker who operated and controlled the IRT subway. Belmont's efforts to preserve his transportation monopoly precipitated a confrontation with the nascent progressive political movement. The progressive reformers wanted to expand the subways to promote dispersal of the population into the outer boroughs of New York, especially the Bronx, Brooklyn, and Queens. Their success marked the end of the era of domination of city government by the mercantile elite.".

"The construction of the subway system - still the world's largest and, at 722 miles of track, long enough to extend from New York to Chicago if all the track were laid end to end - was a monumental engineering feat. Subway tunnels beneath the East River connected Manhattan with Brooklyn and Queens, and other tunnels beneath the Harlem River connected Manhattan and the Bronx. In northern Manhattan the subway lay nearly 200 feet deep beneath solid rock in the vicinity of Fort George; a construction accident there took the lives of ten men, all of them immigrants. (The subway system was built almost entirely by immigrant labor.)" "The subways were a success by e