Complex sentence: The central section, which was designed as a swing bridge to allow shipping to pass, no longer opens and is welded shut, although the rotating mechanism-hydraulic cylinders attached to a drive chain and sprocket-is still visible beneath the bridge.
Split into simpler sentences: The central section, which was designed as a swing bridge to allow shipping to pass, no longer opens and is welded shut. Although the rotating mechanism-hydraulic cylinders attached to a drive chain and sprocket-is still visible beneath the bridge.