Mystic River Drawbridge No. 7, Spanning Mystic River at Boston & Maine Railroad Eastern Route, Somerville, Middlesex County, MA

Significance: Drawbridge No. 7 is apparently the last horizontally folding railroad bridge in the eastern United States. Its technology is representative of the earliest patented movable span bridge in the country (patented by Joseph Ross of Ipswich, Massachusetts, in 1849). The horizontally folding draw was a common railroad bridge type in the Greater Boston area since the 1840s. All except Drawbridge No. 7 have been removed and/or replaced.
Survey number: HAER MA-88
Building/structure dates: 1894 Initial Construction
Building/structure dates: 1933 Subsequent Work
Building/structure dates: 1955 Subsequent Work
Building/structure dates: 1917 Subsequent Work