Rue de Crimee Lifting Bridge (Paris)
The Pont levant de la rue de Crimée (Crimea Street lifting bridge) is a lifting bridge which carries the rue de Crimée over the Ourcq canal at its intersection with La Villette basin. It is flanked by a footbridge (passerelle) which allows pedestrians to cross the canal when the bridge is raised.
Built by the Cie. de Fives-Lille in 1885. It remains in regular use. Renovation was carried out in 2010-2011.
The bridge is raised by hydraulic rams (one at each end). Four cast iron columns guide the corners of the deck. Pulleys on top of the columns guide cables (originally chains) for counterweights.
Casual study of the bridge does little to reveal the mysteries of its workings, especially when it is in its lowered position. Fortunately a set of 1886 drawings is available online [1]. These show details of the mechanism and also the arrangement of tunnels under the canal, one of which included a narrow gauge railway.
See also French Wikipedia entry.