A bascule bridge (also referred to as a drawbridge or a lifting bridge ) is a moveable bridge with a counterweight that continuously balances a span , or leaf, throughout its upward swing to provide clearance for boat traffic. It may be single- or double-leafed.
4-582: The Norfolk Southern Lake Pontchartrain Bridge is a rolling lift trunnion bridge that carries a single-track of Norfolk Southern rail line over Lake Pontchartrain between Slidell and New Orleans, Louisiana, parallel to the Maestri Bridge At 5.8 miles (9.3 km) long, it is the longest railroad bridge in the United States and the longest rail bridge over water in the world. The bridge
8-529: Is used by Norfolk Southern freight trains, as well as the daily Amtrak Crescent passenger train. 30°11′0″N 89°51′8″W / 30.18333°N 89.85222°W / 30.18333; -89.85222 This article about a bridge in Louisiana is a stub . You can help Misplaced Pages by expanding it . Bascule bridge The name comes from the French term for balance scale , which employs
12-411: The counterweights to the span may be located above or below the bridge deck. The fixed- trunnion (sometimes a "Chicago" bascule) rotates around a large axle that raises the span(s). The Chicago bascule name derives from the location where it is widely used, and is a refinement by Joseph Strauss of the fixed-trunnion. The rolling lift trunnion (sometimes a "Scherzer" rolling lift), raises
16-479: The same principle. Bascule bridges are the most common type of movable span because they open quickly and require relatively little energy to operate, while providing the possibility for unlimited vertical clearance for marine traffic. Bascule bridges have been in use since ancient times, but until the adoption of steam power in the 1850s, very long, heavy spans could not be moved quickly enough for practical application. There are three types of bascule bridge and
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