This bridge was once a railroad siding that crossed onto Isle La Plume from the Wisconsin mainland at La Crosse. The railroad has since been removed, and the bridge converted to carry a wooden pedestrian and bicycle path, plus what appears to be a water main. The bridge is just wide enough for a car to cross the Isle La Plume Slough, so the city installed the orange posts to keep vehicles off the bridge.

If anyone knows anything else about this bridge, please let me know.