The Atlantic Avenue Tunnel, as it is now called, was built in seven months in 1844 by the Long Island Rail Road [Map] to relieve congestion in downtown Brooklyn. [Photos from a March tour and a 1995 of the tunnel.] It was part of a rail network that eventually took passengers to Boston. For mainly political reasons, it was closed not too many years after it opened; the last train ran through it in 1859. In 1861, the tunnel was sealed up. The tunnel is 17 feet high and 21 feet wide; the navigable portion of the tunnel is from 1700 to 2000 feet overall.
In time, it became sort of an urban legend, and many stories were born about it and what uses some people may be putting it to. There were also various attempts to find it throughout the years. In the early '80s, Bob Diamond heard about it, and became captivated. [Images from Bob Diamond] He made it his mission to locate it, and through several years of research and physical work, he entered the tunnel. Occasional tours of the tunnel are given by Diamond, which end in a trip at the Brooklyn Trolley Museum, which is operated by Diamond. The Transit Museum also occasionally sponsors tours of the tunnel (the most recent was on March 14).
For more information, contact the Brooklyn
Historic Railway Association at (718) 941-3160, or e-mail Bob Diamond