Thirty feet below Atlantic Avenue in Brooklyn, there’s a tomb of stone. Its story is of a steam locomotive suspended in time, a man with a vision, and a city that holds all the keys.

The world’s first subway tunnel was nearly forgotten until an urban explorer located it 120 years after it was sealed. The question is, did he also find a locomotive buried under Atlantic Avenue in Brooklyn?

In 1844 the Long Island Rail Road chose to bury a section of the line under Atlantic Avenue in Brooklyn to avoid accidents between the train and local pedestrians. Fifteen years later the Cobble Hill Tunnel was sealed, possibly with a locomotive inside, and its location was lost in history.

Fast forward to 1980. A Brooklyn man named Bob Diamond hears a comment on a radio show about an unknown tunnel underneath the city. Using old maps, he digs his way from a defunct utility hole 30 feet under Atlantic Avenue.

With the help of friends, Bob Diamond hauled off the dirt bucket by bucket from the hole in the middle of the street. All his digging paid off when he reached a concrete wall. He says that when he smashed through, a rush of cold air came out.

Diamond found himself peering down into a vast, open space. He knew he had located the Cobble Hill Tunnel, and it was intact. 

The tunnel was half a mile long and massive, with enough room for two train tracks side by side, A 17′ arched stone ceiling, and limestone block walls 22′ apart. An absolute engineering marvel for the age. Wooden stairs had to be built to get Bob and friends down to the floor. The far end of the tunnel is capped by a very thick stone wall.

Diamond spent the next 30 years leading tours in the tunnel. He started a trolley museum with plans of opening up and running trolleys through Cobble Hill’s famed tunnel.

One thing remains a mystery. The tunnel is said to have been sealed with an 1836 wood-fired locomotive inside. It was noted in a historical book as being the place that John Wilkes Booth may have hid his diary. 

That locomotive has yet to be found. Diamond’s logical conclusion is that it, along with the tunnel’s lost marble station, existed on the other side of that stone wall at the other end of the tunnel.

A private engineering firm was hired to scan the area from above ground with special equipment. They determined that there was a large steel object buried below at the end of Atlantic Street. 

The story caught the interest of the National Geographic Channel. They worked together with the city and Diamond to plan an excavation of the wall at the end of the tunnel and film a documentary about the process.

In 2010 the whole thing came to a halt. The city and the executives at National Geographic are rumored to have had disagreements. The city canceled the documentary and sealed the tunnel once again, banning Diamond and everyone else from entering.

The city is denying access to this day, and the story is fading into history once again. It seems we may have to wait another century before we know the truth.

Why is it so important that we save this tunnel? So what if there’s a locomotive buried under Atlantic Avenue? 

A rich history makes for a prideful neighborhood. And a prideful neighborhood makes for a good neighborhood. If the tunnel were opened and the trolleys installed, it would increase business and tourism. Maybe Cobble Hill Tunnel will see the light of day again.

Visit Bob Diamond’s website, www.BrooklynRail.net

Born and raised in Upstate New York, Mathew lives in a wooded valley north of the Susquehanna River with his wife and kids. His first book "Simple Sutras" was published in 2014