Hydraulic Bridges

From Theatre Royal Drury Lane (1663 - present)

Installed in the Theatre Royal in the late 1890s after the Vienna Opera House had removed them, these bridges are fully operational and are protected by English Heritage. 

If a large scale show requires the understage area to be cleared, the bridges and associated mechanisms must be carefully removed by experts, put into storage, and reinstated (and tested) once the show finishes its' run. 

Theatres Trust website

Dorothea Restorations