Science Fair Project Encyclopedia
Manhattan Bridge
The Manhattan Bridge is a suspension bridge that crosses the East River in New York City, connecting Lower Manhattan with Brooklyn. The bridge was opened on December 31, 1909 and was designed and built by Polish bridge engineer Ralph Modjeski with the deflection cables designed by Leon Moisseiff, who later designed the infamous Tacoma Narrows Bridge in 1940. It has 4 vehicular lanes on the upper level (split between two roadways), and 3 vehicle lanes, 4 subway tracks, a walkway and a bikeway on the lower level. The upper level has 2 lanes in each direction, and the lower level can be one-way in peak direction or have 2 lanes in one direction and the other in the opposite direction.
A new pedestrian walkway opened on the south side of the bridge in June 2001. It was also used by bicycles until late summer 2004, when a dedicated bicycle path was opened on the north side of the bridge.
- Span 1,470 ft (448 m)
- anchorage-anchorage length 2,920 ft (890 m)
- total length 6,855 ft (2,089 m)
Subway tracks
The bridge has four subway tracks on the lower level, two on each side. All four are in use; the two north tracks currently carry service and the two south tracks carry service. On the Manhattan side, the south tracks connect to the Manhattan Bridge Line, which feeds the express tracks of the Broadway-BMT Line, and the north tracks connect to the Chrystie Street Connection (which feeds the IND Sixth Avenue Line). Between the bridge and the Broadway-BMT Line, there is one station, at Canal Street ; the line merges with the Broadway-BMT Line in the middle of its own Canal Street station , which only serves the local tracks.
On the Brooklyn side, the four tracks merge in a flying junction to create a four-track subway, which quickly merges with the two-track BMT Fourth Avenue Line (). That line soon enters DeKalb Avenue station, after which two tracks split to form the BMT Brighton Line () and the other four continue on the BMT Fourth Avenue Line ().
Due to the tracks being on the outside of the bridge, passing trains cause the bridge to tilt and sway. When compounded with a lack of maintenance by the New York City Department of Transportation , this led to the need to close the tracks for repairs. The north tracks, which had been more heavily used, were closed first, from 1986 to 1988. The south tracks were closed in 1988, and except for a brief period in 1990, remained closed to trains until July 22, 2001. The north tracks were again closed during off-peak hours in 1995 and full time again in 2001, until February 22, 2004, after which both tracks were again open.
When the bridge first opened, the tracks didn't connect to any others. The Manhattan Bridge Three Cent Line, a streetcar company, began operations on the subway tracks in 1912 until (later BMT) trackage was connected to the bridge in 1915, and the trolleys were moved to the upper level roadways. In 1929, trolley service ended over the bridge.[1]
The four subway tracks came under operation by the BRT, which also had two tracks each over the Brooklyn Bridge and Williamsburg Bridge, as well as three two-track tunnels under the East River (Montague Street Tunnel , 14th Street Tunnel and 60th Street Tunnel ). The Brooklyn side has not changed at all; it has always been fed by the four-track connection from the Fourth Avenue Line . The Manhattan side has changed, however. When originally built, the two north tracks connected into the Manhattan Bridge Line to the Broadway-BMT Line (where the south tracks now connect), and the two south tracks curved south to join the Nassau Street Line along tracks now used for storage (and no longer connected to the bridge).
Concurrent with the building of the Chrystie Street Connection (opened November 26, 1967) to connect to the north tracks, the south tracks were rerouted to the Broadway-BMT Line connection, and the connecting tracks to the Nassau Street Line were closed.
External links
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