Bridge is now doomed. Scheduled for closure and demolition. Or maybe replacement.
The NBI's date of construction differs widely. Sections have been replaced, the eastern stringer half over railroad tracks and port roads in particular after a fire around 1930. Given the original design resembled the Murray Morgan/City Waterway, a date of 1913 seems to be accurate.
Added other details to bridges nearby, if anyone, you know likes those sorts of things.
To confirm your suspicion Nathan:
In September of 1966 the upper section of the vertical lift along with some other parts were removed by Early Construction Co. at a cost of $15,000. This made the bridge inoperable. The power lines located next to the bridge were then attached to the remaining towers to cross the waterway.
In June of 1979 Willamette Western scrapped the remainder, 175 tonnes of steel in all, including the cable wheels, counter weights, and control house. This process cost $167,000.
To give you a visual: It originally was a smaller version of the Murray Morgan/City Waterway bridge to the West.
Sources – various newspapers I sorted through at the library.
This appears to be a vertical lift bridge which had its towers and machinery removed.