The 116-Year-Old Tunnel Keeping New York Connected Is Rotting

Beneath the Hudson River, the 116-year-old North River Tunnels carry 450 Amtrak and NJ Transit trains a day into New York Penn Station, and they are slowly rotting from the inside. If you ride Amtrak on the Northeast Corridor between Washington, New York, and Boston, or take NJ Transit into Manhattan, you go through these two single-track cast-iron tubes. There’s no backup rail tunnel under the river into Penn Station. In 2012, Hurricane Sandy flooded both tubes with millions of gallons of brackish seawater. Crews pumped the water out within days, but the salt had already soaked deep into the 1910 concrete bench walls, and it’s still eating away at the concrete, steel, and high-voltage power cables. This October, a tunnel boring machine finally started digging the first new Hudson River rail tunnel in 116 years, as part of the Gateway Program. It isn’t scheduled to open until 2035. This documentary looks at how the Pennsylvania Railroad dug the original tubes through river silt in 1905, the chemistry behind the saltwater corrosion, why engineers can’t close one tube for repairs without crippling the East Coast economy, and whether the 1910 tunnels can hold out for nine more years. Chapters 0:00 The tunnel everyone depends on 0:54 A railroad that stopped at the river 1:29 Digging under the Hudson by hand 2:31 The tunnel that floats 2:58 Inside the tubes 3:45 The night the ocean got in 4:20 Why the salt is still winning 5:53 Why not just close it? 6:48 A deadline and a long road 7:38 The machines start digging 8:22 Turning river mud into rock 9:25 Can the old tunnel make it? 10:06 One way across