The construction of New York’s first subway was one of the most public and dangerous engineering projects in American history. It was built by cutting open the busiest streets in the country from the top down, holding the city’s own gas and water lines in midair, and blasting through solid rock under buildings full of people. By 1900, New York had roughly 3. 5 million people crammed onto a narrow island, moving by horse, cart, and slow-walking carriage.
Elevated steam railways dropped ash and cinders on the streets below and still could not handle the crowds. The city was choking on its own growth, and the only room left to expand was down. The city signed the subway contract on February 21, 1900, agreeing to pay $35 million for construction. John B.
Macdonald, an Irish immigrant and experienced tunnel contractor, won the job but could not raise the required cash and bonds. August Belmont, one of the wealthiest financiers in America, stepped in to bankroll the project, forming the company that would own and run the line. Over both men stood chief engineer William Barclay Parsons, hired years earlier at age 35 to study whether a subway was even possible and to design it. He mapped the route and, crucially, mapped the rock beneath it.
Ground was broken on March 24, 1900, with about four and a half years to finish. The job was divided between two methods. Soft ground was handled by cut and cover, a brutal, open-air technique that tore up whole avenues. Crews excavated a trench about 20 feet deep down the middle of the street, bracing the dirt walls with timber and cutting straight through the buried network of gas mains, water pipes, sewers, and electrical conduits.
Those utilities could not be shut off for years, so workers held them up on timber cradles while digging underneath and around them. Live gas pipes and water mains hung in the open air over the diggers while street traffic continued overhead on plank bridges. Workers then planted steel I-beams, poured concrete around them, and rebuilt the street on top before moving to the next block. About 52 percent of the line was built this way, extending a little over 10 miles.
Many of the steel beams still visible on subway platforms today are the ones set in those open trenches more than a century ago. The harder problem was Manhattan schist, the hard gray rock the island is built on. It does not sit at a steady depth. It rolls like a frozen wave — rising to within 16 feet of the surface near 30th Street, plunging to around 163 feet near today’s Tribeca, and climbing again.
Where the rock came up, crews had to blast through it. Drillers bored holes about 7 feet into the stone, packed them with dynamite, and cleared the shattered rock by mule cart. They repeated this thousands of times, foot by foot, often directly beneath occupied streets and buildings. The longest rock tunnel ran more than 2 miles near Fort George, the second-longest tunnel of its kind in the country at the time.
At 191st Street, the line runs about 180 feet down, deep enough that elevators were later needed just to reach the platforms. To cross the Harlem River into the Bronx, crews sank two iron tubes about 16 feet across and more than 600 feet long, roughly 39 feet below the waterline. The tunnels were pressurized with compressed air to keep water and mud out, and the men who worked inside were called sandhogs. Coming up too fast caused decompression sickness, known as the bends, which could kill or leave workers crippled.
It was a common danger on river tunnel jobs of the era. At the peak of construction, around 7,700 laborers worked on the line, most of them immigrants. Irish, Italian, German, and Greek workers dug alongside African-American laborers. Irish tunnel men carried on a tradition going back to the Brooklyn Bridge, while Italian immigrants took most of the pick-and-shovel work in the open cuts.
Pay was low. An unskilled laborer earned about $2 to $2. 25 a day. Skilled men made about $2.
50, and a miner at the top of the pay scale took home about $3. 75. The dangers were never fully counted. On January 27, 1902, a crew working under Park Avenue near 41st Street tried to thaw frozen dynamite by a small fire, then left it unattended.
The fire spread and the entire supply exploded. Master mechanic William Tubbs ran in with a hose and was killed where he stood. At least five people died, around 125 were hurt, and the blast tore a 30-foot crater in the street. Nearly every window on two sides of the Murray Hill Hotel was blown out, and 250 guests were cut by flying glass in their own rooms.
On October 24, 1903, near Fort George at the northern tip of Manhattan, a crew set off about 2 pounds of dynamite in the rock tunnel. Nothing happened at first. About half an hour later, a slab of the tunnel roof roughly 44 feet long, up to 5 feet thick, and weighing about 300 tons came down without warning. Ten workers were killed, seven of them Italian laborers.
The foreman, 45-year-old Timothy Sullivan, died with them. Engineers concluded the main cause was not the small blast but heavy rain, which had soaked into natural seams in the schist and loosened a slab that was already waiting to fall. At least 16 men died in those two incidents alone, but the total death toll was never fully recorded. Men were killed by premature blasts, smaller cave-ins, falls, machinery, and crushing between cars.
Others died later from injuries and disease. The engineers are remembered, the workers mostly are not; their records survive mainly as wage books and small items in accident columns. The line also needed its own power. In 1904, the city did not have enough electricity to run a railroad, so Belmont’s company built its own plant on the West Side, filling a block between 58th and 59th Streets near 11th Avenue.
Architect Stanford White designed the building, wrapping a raw coal-burning power plant in the form of a grand Beaux-Arts palace. When finished, it was the largest power plant in the world, built to run up to 800 subway cars at once and staffed by more than 400 people. It still stands and still generates power today. The first line opened on October 27, 1904, at 7 p.
m. , running about 9. 1 miles from City Hall, up the East Side, west along 42nd Street, and then north up Broadway, with 28 stations. Roughly 150,000 people rode it on opening day, paying a single 5-cent fare for the wonder of moving underground.
The line was designed to carry about 600,000 riders a day, a figure once seen as absurd, and it reached that capacity within about a year. The subway reshaped the city almost overnight. Neighborhoods along the route that had been too far from downtown filled quickly, with some districts growing by more than 100 percent in the years after opening. The line pulled New York north along its tracks, a shape the city still has today.
The streets healed over, the trenches were paved shut, and the city largely forgot how it had all been built. But the steel, the concrete, and the rock remain beneath the streets, along with the men who went into the ground to build it.