Moveable bridge

Common card · No. 464915

A moveable bridge, or movable bridge, is a bridge that moves to allow passage for boats or barges. In American English, the term is synonymous with drawbridge, and the latter is the common term, but drawbridge can be limited to the narrower, historical definition used in some other forms of English, in which drawbridge refers to only a specific type of moveable bridge often found in castles. An advantage of making bridges moveable is the lower cost, due to the absence of high piers and long approaches. The principal disadvantage is that the traffic on the bridge must be halted when it is opened for passage of traffic on the waterway. For seldom-used railroad bridges over busy channels, the bridge may be left open and then closed for train passages. For small bridges, bridge movement may be enabled without the need for an engine. Some bridges are operated by the users, especially those with a boat, others by a bridgeman (or bridge tender); a few are remotely controlled using video-cameras...

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