Complex sentence: In 1969, the parapet on the north (upstream) facade of the bridge was removed and was replaced with a cantilevered walkway and steel railing.
Split into simpler sentences: In 1969, the parapet on the north (upstream) facade of the bridge was removed. There is a steel railing, added in 1969 which temporally replaced one parapet with a cantilevered walkway and steel railing.