The Cobble Hill Tunnel: What’s Inside America’s Oldest Subway?

The Cobble Hill Tunnel

It’s no longer much of a secret since it was rediscovered in 1981, but Cobble Hill Tunnel used to be considered some type of myth based off vague mentions of an unfinished project and a short piece by Walt Whitman. Supposedly, this tunnel had a walled-up locomotive, and the missing pages from John Wilkes Booth’s famous diary.

Robert Diamond was 18 years old when he pieced together where the cobble hill tunnel was: Atlantic Avenue and Court Street in Brooklyn. He somehow got a permit to open up a manhole, and crawl on his stomach down an opening no wider than a few feet, eventually hitting a concrete wall.
Over the next years, he dug out the tunnel and got to work studying it. There is a second wall that has never been dismantled, and testing has shown that there is likely a large, metal object in the next room (very possibly a locomotive).


It wouldn’t be surprising if there was a locomotive behind that wall. The Cobble Hill Tunnel was started in 1844 and outdates all other subway tunnels in North America, making it one of the oldest known. Before the construction of above-ground subways, the Cobble Hill tunnel was proof that someone had the great idea of using steam powered trains in unventilated tunnels.
Locomotives were often used to tow building materials, but the problem with that was that once you got that behemoth of machinery underground, it was there to stay.
The tunnel was going to be part of a link between Boston and New York. But with competing rails all around, it taking too long for action to be taken towards completing the project.

The Tunnel Was Sealed in 1861

So, when the city of New York shut the operation down due to John A. King’s conflicting personal interest in stock shares, it was more cost-effective to wall everything up, a very common practice.
After it was sealed, the tunnel is rumored to have been in use by the mob, speakeasies, and bomb makers. But eventually Cobble Hill Tunnel and the locomotive drifted from common knowledge, and soon became the conspiracy, with the missing diary pages stowed inside.
Up until recently, Robert Diamond had continued to work in and for Cobble Hill Tunnel- until safety citations caused his contract to be terminated.

There are a lot of people who say they believe John Wilkes Booth’s pages are in there. And if they are, it will be another incredibly intriguing part of the tunnel’s history. Although the truth behind the history of this tunnel isn’t as intriguing as the myth, I’m more curious about how many other places have been forgotten like Cobble Hill Tunnel.



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