Between 1863 and 1867, Cornelius Vanderbilt gained control of the NY&HRR, the Hudson River Railroad, and New York Central Railroad and consolidated them into the New York Central and Hudson River Railroad in 1869. He then built a connecting line along the Harlem River’s northern and eastern banks, running from the Hudson River Railroad in Spuyten Duyvil, Bronx, to the junction with the Harlem Railroad in Mott Haven, Bronx, as part of the Spuyten Duyvil and Port Morris Railroad.
This not only set the stage for Vanderbilt’s wealth and power via transcontinental railroads, but for a transportation hub in Manhattan where all his railroads could converge.
Grand Central Depot, which opened in 1871, was expected to reach capacity by the 1890s, but it only took until the mid-1880s for its 12 tracks to fill. An annex was built in 1885 with an additional 7 tracks. By 1897 it was at capacity again.