Movable bridge

Sign 128 of the StVO for movable bridges (abolished in 2013)

A moving bridge is a bridge whose structure can be moved as a whole or in parts. Movable bridges are usually used to temporarily release the clearance under the bridge required for the passage .

Applications

A movable bridge is mainly used to bridge crossing ship routes and in ports , where building a fixed bridge with the necessary clearance would be too expensive. However, there are also bridges that give the torrent below more space in the event of a storm. This is a way of preventing the build-up of driftwood, which can cause the stream to overflow or, in extreme cases, cause the bridge to fail.

In some cases, movable bridges are also used to guide traffic routes over railway lines. As a special feature, it should be mentioned that from 1898 to 1964 the access road from Stansstad to Engelberg in Switzerland with the Grünenwald bascule bridge crossed the Lucerne-Stans-Engelberg railway , where the overhead line for the railway was raised and lowered. There is still a bascule bridge in Australia in the 21st century that runs a sugar cane railway over the main Queensland Rail near Bundaberg .

Security and signaling

In the Netherlands there is a traffic light for shipping with the rule that the red-red position announces the temporary deactivation (closure) and the simultaneous lighting of the green and red light signals to the skippers that the switching of the bridge will soon be started can. In the normal position, the skipper has to call the bridge keeper by radio if he has not noticed the approaching ship.

The roadway and sidewalks are necessary technical measures as necessary, traffic lights and or flashing light and often barriers secured. In the case of railroads, light signals also block the road via tracks, which can be triggered remotely or switched by a switch contact.

Different types of movable bridges

Bascule bridge	Lift bridge	Swing bridge	Folding bridge
Drawbridge (military: drawbridge )	Sink bridge	Tipping bridge	Thrust bridge
Rolling bridge ( example )	Lift bridge (table bridge)	Wippbrücke after William Donald Scherzer , example	Transporter bridge (bridge in the broader sense)