My research suggested removal of the lift portions of the bridge occurred in two projects, one in 1966 and the other in 1979. My guess is machinery was removed in 1966 and the tower removal was 1979. http://historicbridges.org/bridges/browser/?bridgebrowser=wa...
Aerial imagery from historic aerials shows lift towers in 1940 and 1968/69
I wonder if this former vertical lift bridge that had the machinery counterweight and towers removed is similar identical or resembled the Murray Morgan bridge crossing the city/ Foss waterway?
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.