As a kid growing up in the area, I remember the bridge was painted with a silver aluminum paint – but was given this new paint job in 2001. The Tower Bridge replaced the 1911 M Street Bridge in Sacramento, which was originally a “swing through-truss railroad bridge.” The bridge style represents a rare use of Streamline Moderne* architectural styling in a lift bridge, making it an outstanding expression of the social and architectural climate of the period of construction. The lift span towers were sheathed in steel to streamline its appearance. The American Institute of Steel Construction* gave the Tower Bridge an honorable mention for its Class B prize bridge award in 1935.
(* notes from Wikipedia)