A similar bridge, but with only one lifting section, is located in Gloucester, where the Sharpness to Gloucester canal reaches the docks. A massive counterweight sits over the road. Numerous swing bridges are found along the canal, which traverses the flood-plain of the river Severn. These bridges are turned about a vertical axis by means of a geared windlass. This one, at Fretherne, is fully open, and a boat is passing through.
Barriers warn people on the road to stop.
Some other types of bridge use a rolling bearing, instead of rotating on a horizontal axle. This one is Peto's bridge in Bristol. The arc and track have large teeth that prevent slipping. The two large objects that look a bit like funnels are the counterweights. Perhaps they are intended to look like lilies or ear-trumpets.