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Grand by Design: An Engineering Marvel
Behind the majestic design and décor of Grand Central Terminal is a triumph of engineering and ingenuity. Grand Central didn’t just do things better than other train terminals. It did them differently. It pioneered new approaches to organizing space. It invented new technologies. And it overcame the daunting challenge of building a vast, durable, efficient train station—much of it buried deep underground—in the bustling center of the nation’s busiest city.
More and more people were riding more and more trains. Grand Central needed additional tracks…and efficient ways for passengers to reach those tracks. With little space to spread out, the station dug down. Engineers created a vast underground structure: four tracks in the Park Avenue tunnel and a 123-track train shed designed to support heavy locomotives plus the weight of the buildings overhead. A series of crossovers let trains reach any platform from any track. Inside the station, meanwhile, pedestrian ramps took passengers swiftly from level to level. The design also included a centralized hot water heating system—the largest of its kind at the time—with four miles of pipe serving the station and surrounding buildings.
Grand Central Terminal
Inventing the Future
Grand Central was bigger and newer than its predecessor. It was also a technological pioneer. For the changeover from steam engines to electricity, engineers William Wilgus and Frank Sprague designed a groundbreaking third rail. Train cars made contact with the underside of the power rail, whose top and sides were sheathed in wood to protect workers from electrocution.
The New York Central completed the first phase of electrification in 1906. Here, the line’s first electric train stands outside the Grand Central train shed after its first test run from High Bridge on the Harlem River in Northern Manhattan.
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Grand Central Terminal Powerhouse
Powering Grand Central
Steam engines generate their own power. Electric engines must get it from power plants. In 1910, the railroad built a state-of-the-art electrical substation on 50th Street that converted the city’s alternating current electricity to the direct current used by locomotives. The facility also featured 14 coal-driven boilers producing hot water to heat Grand Central and neighboring buildings.
The railroad’s electrical substation and heating plant (the smokestacks in the foreground) opened in 1919 at 50th between Lexington and Park Avenues. It converted alternating current from a power plant farther north to direct current for locomotives, and reduced the voltage for signals and clocks that used alternating current.
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Grand Central Terminal Powerhouse
In addition to its role as an electrical substation, the 50th Street facility produced hot water for heating buildings throughout the area. Chutes carried ashes from the coal-driven boilers to tracks in the basement. The building was demolished in 1930 to make way for the Waldorf-Astoria Hotel.
In 1930, the 50th Street electrical substation was demolished to make way for the Waldorf-Astoria Hotel. Where to put a new power plant for Grand Central? Under Grand Central. Substation 1L housed electrical generators 100 feet below the terminal. The giant rotary converters on the left were upgraded with modern equipment in 1989.
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Grand Central Terminal
Keep the Traffic Flowing
Most railroad stations built in the early 1900s relied on one centrally located tower to oversee operations. Grand Central has five. The terminal’s vast network of tracks, divided into two levels, required the largest traffic control system ever built at the time. Its signal towers communicate closely with each other to route trains through a maze of tracks.
Grand Central’s main signal tower was a four-story structure deep underground near 49th Street. Its top two stories (Express Level) were named Tower A, and lower two (Suburban Level) Tower B. As trains arrived or departed, the Tower Director called out the numbers of levers that controlled individual switches and signals.
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Grand Central Terminal
As one employee put it, control center renovations in 1993 brought Metro-North “from the year 1913 to the year 2000.” Computers and a 44’ model board let operators route trains by typing commands or pushing buttons rather than by pulling levers. The Control Center was upgraded again in 2010.
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Grand Central Terminal
Feats of Engineering
Dismantling the Old Train Shed, 1908
Before construction crews could build the new Grand Central, they had to un-build the old one. Dismantling a train shed in the middle of Manhattan is no easy task. By day, workers demolished the existing structure section by section. By night, crews lowered discarded material to railcars, which carried it away.
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Grand Central Terminal
Building Grand Central Terminal, 1912
Nearly 30,000 tons of steel supported the outer skin of granite and limestone covering the main terminal building.
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Grand Central Terminal
Excavating the Grand Central Yard, 1904
The new station’s vast underground labyrinth of tracks and platforms also required a lot of digging. Workers borrowed techniques recently developed for the Panama Canal to excavate more than three million cubic yards of rock and dirt—roughly four times the volume of the Empire State Building. Hopper cars carted off this material, which the railroad used to construct a new train yard at Croton-on-Hudson.
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Grand Central Terminal
Building the Train Shed, 1911
Grand Central’s double-decker train shed begins to emerge from the construction site in this photo looking north from 45th Street.
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Park Avenue and 45th Street
No Basements? No worries!
Ever wonder why you need an escalator to reach the elevator lobby in the MetLife Building, the skyscraper north of Grand Central? Burying the train tracks underground made it possible to build buildings above them. It also meant that those buildings had no basements for mechanical systems. In the MetLife Building, elevator equipment—normally housed underground—fills the first three floors
The new terminal opened the door to new development. Park Avenue was transformed into a broad boulevard over the train tracks. New York Central leased the “air rights” to developers, who built above the tunnel.
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