I Street Bridge is the heaviest swinging center bridge in the United States.
Built in 1911, the I Street Bridge is 363 feet long, weighs over 7 million lbs., and has two decks; one for highway traffic and one for railroad traffic.
The swing-span bridge pivots 90 degrees clockwise to allow ships access to the Sacramento River, and carries approximately 10,000 cars and trucks and 40 railroad trains every day.
As of early 2017, the City of Sacramento is planning to reroute car, bus, and bicycle traffic onto a more modern bridge upriver in coming years. However, railroad traffic will remain on the structure even after the new bridge is built.
Just downstream of the bridge on the east side of the river is an information board, entitled “Prisoner of the River,” relating to the vessel, LaGrange, a floating prison which sank there in 1859.
If you sign up for the River Ferry Cruise you will go under this bridge. The view is pretty stunning. There is a bicycle/walking trail along the eastern shore of the Sacramento River near the California State Railroad Museum that is a particularly good vantage point to see the bridge swing open. (A short way downriver, also visible from this trail, is the Tower Bridge, which is a vertical-lift type movable bridge.)
Clancy's comment: Amazing structure, and I doubt that there are many swing bridges left.