Joralemon Street Tunnel

The Joralemon Street Tunnel, originally the Brooklyn–Battery Tunnel, is a pair of tubes carrying the IRT Lexington Avenue Line of the New York City Subway under the East River between Bowling Green Park in Manhattan and Brooklyn Heights in Brooklyn, New York City. The Joralemon Street Tunnel served as an extension of the Interborough Rapid Transit Company 's first subway line from the Bowling Green station in Manhattan to the IRT Eastern Parkway Line in Brooklyn.

The tubes were constructed using the shield method and are each 6,550 feet long and 15.5 feet wide. The tubes are lined with cast-iron "rings" formed with concrete. Their maximum depth is 91 to 95 feet below the mean high water level of the East River, with a maximum gradient of 3.1 percent. The construction of the tunnel also saw the conversion of 58 Joralemon Street, in Brooklyn, into a ventilation building and emergency exit.

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