That is exactly what happened. As the city developed northward, traffic in and out of the new station grew so rapidly that it had to be expanded several times. Before long, there was a growing chorus of complaints from the owners of nearby houses and offices about noise and filth and danger to pedestrians. The clamor eventually forced the New York Central to construct a tunnel down the middle of Park Avenue to carry most of its trains in and out of the city, and a modern terminal at the end of it, at 42nd Street, that the world knows today as Grand Central.

The new station and train yards consumed nearly 50 acres and were constructed over a decade at a cost of $2 billion in today’s dollars. It was the first station to have clean, electrified trains arrive on two levels of underground track, one for commuter trains, the other for long-distance service like the luxurious 20th Century Limited to Chicago. The station had the capacity to handle more than 1,000 railcars at any given time, with 30 platforms reached by ramps and underground concourses.

Once in the station, ladies and gentlemen could go to separate waiting rooms and lounges to have their hair cut, have their shoes shined or change into a fresh outfit. Restaurants on the mezzanines overlooked the marbled main concourse, and the now famous Oyster Bar below.

The majestic main concourse was 275 feet long and 120 feet wide, flanked on both ends by grand marble staircases, underneath a massive concave ceiling on which was painted the constellations of the stars. The New York Times, in a special section, proclaimed the newly opened Grand Central to be the world’s greatest train station, “a monument, a civic center or, if one will, a city.”

From its inception, however, Grand Central was more than a train station — it was a real estate development project. New York Central’s original investment was premised on its ability to develop or sell the air rights for the land around the terminal building once the underground tracks and platforms had been completed and covered. According to Sam Roberts, the New York Times columnist who wrote a book on the occasion of Grand Central’s centennial, the assessed value of property in the immediate area around the station more than doubled within three years of construction. A decade later, it had doubled again, creating a huge return for Vanderbilt and his railroad and a bonanza for the city’s economy.

With Grand Central as its anchor, Midtown Manhattan became the commercial, residential and cultural heart of New York. The great hotels of the era, including the Ambassador, the Biltmore, the Commodore and the Waldorf-Astoria, sprang up, while many of the nation’s biggest corporations moved their headquarters uptown to the nearby Chrysler Building, Empire State Building and ornate New York Central Building. For apartment living, Park Avenue became one of the city’s most prestigious addresses — by 1920, it was reported that 100 millionaires were living at the single address of 270 Park. And where the swells came, their clubs and nightclubs and favorite restaurants soon followed.

Grand Central’s economic impact was also felt in the suburban commuter towns that sprouted along the tracks leading away from the city — towns such as White Plains and New Rochelle in New York and Greenwich and Darien in Connecticut. These suburbs also became part of the city’s economic ecosystem, and without them, New York would never have become the economic engine it is today.