Spanning the Contoocook River in New Hampshire the double-web Town lattice truss bridge is one of just eight remaining in the U.S.
Built in 1889 by the Boston & Maine Railroad, the double-web Town lattice truss covered bridge crosses the Contoocook River, one of an estimated 100 of its type on the railroad at the turn of the century. The type was patented by Ithiel Town in 1835 to solve the problem of single lattice bridge superstructure warping under heavy loads. By doubling the web the truss became more rigid under load. [1]
The bridge has survived floods in 1936 and 1938, and carried railroad traffic until 1962. It was later used as a warehouse until it came under the ownership of the New Hampshire Division of Historic resources in 1990. It is now one of eight surviving covered wood railroad bridges in the U.S.
[1] The recording of this bridge was part of the Historic American Engineering Record, a project of the National Park Service. The field work was completed under the direction of Christopher Marston, project leader; Naomi Hernandez, summer team supervisor; and Richard O’Conner, senior historian. The field team included Dr. Philip S.C. Caston, ICOMOS, Germany; architects Amy Beth James and Vuong Dang of University of Arkansas; William Dickinson, University of Pennslyvania; Arnol Kriesel and Silvia Nadine Bauer, ICOMOS Germany; Michiko Tanaka, ICOMOS Japan; and Doug Parker, University of Oregon. Historians were Lola Bennett, Stow, Massachusetts; and Mark Brown, State College, Pennsylvania. Engineering analyses were produced by Francesco Lanza, ICOMOS Italy, working with John Ochsendor, Massachusetts Institute of Technology; Dorottya Makay, ICOMOS Romania, working with Justin M. Spivey of Robert Silman Associates, New York; and Megan Reese working with Dario Gasparini of Case Western Reserve University. Photography was by Jet Lowe, HAER photographer.