From Wikipedia

Grand Central

Part One/Two

Grand Central Terminal (GCT) — sometimes called Grand Central Station or simply Grand Central — is a terminal station at 42nd Street and Park Avenue in Midtown Manhattan in New York City. Built by and named for the New York Central Railroad in the heyday of American long-distance passenger trains, it is the largest train station in the world by number of platforms: 44, with 67 tracks along them. There are on two levels, both below ground, with 41 tracks on the upper level and 26 on the lower, though the total number of tracks along platforms and in rail yards exceeds 100. When the Long Island Rail Road's new station, below the existing levels, opens (see East Side Access), Grand Central will offer a total of 75 tracks and 48 platforms. The terminal covers an area of 48 acres (19 ha).

The terminal serves commuters traveling on the Metro-North Railroad to Westchester, Putnam, and Dutchess counties in New York State, and Fairfield and New Haven counties in Connecticut.

Although the terminal has been properly called "Grand Central Terminal" since 1913, many people continue to refer to it as "Grand Central Station". Technically, "Grand Central Station" is the name of the nearby post office, as well as the name of a previous rail station on the site, and is also used to refer to a New York City subway station at the same location.

Video architectural tour of Grand Central Terminal
(High-res version on Internet Archive)