{"nrhp_refnum":"97000383","name":"Camelback Bridge","other_names":["Illinois Central Railroad Bridge No. A797-14"],"category":"structure","location":{"address":"Virginia Ave., across the Constitution Trail","address_restricted":false,"city":"Normal","county":"McLean County","state":"IL","lat":40.49830874200006,"lon":-88.98258778699994,"geom_source":"nps_gis"},"listed_date":"1997-05-15","is_nhl":false,"nhl_designated_date":null,"areas_of_significance":["Engineering"],"significance_levels":["local"],"summary":{"what_it_is":"A 1906 timber and iron bridge carrying Virginia Avenue over the former Illinois Central Railroad line, now the Constitution Trail, in Normal, McLean County, Illinois. It was built by the Illinois Central Railroad.","why_significant":"The nomination argues it meets Criterion C in engineering because it combines a timber king post pony truss with twelve wrought iron Phoenix columns dating from the 1860s. It is described as the only known functioning king post truss bridge in Illinois and one of only two known Illinois bridges using Phoenix columns. It is considered locally significant.","narrative":"Carrying Virginia Avenue over the Constitution Trail in Normal, Illinois, this humped timber and iron bridge was built in 1906 by the Illinois Central Railroad. It crosses the former rail line, and its raised center let steam locomotives pass beneath while town traffic crossed above. The bridge is about 116 feet long, with a 32-foot central span formed by a timber king post pony truss. Twelve wrought iron Phoenix columns, stamped with an 1862 patent date, support the approach spans and were probably salvaged from an earlier bridge. Despite its popular name, the bridge is not a true camelback design. It is listed for its engineering significance: it is the only known functioning king post truss bridge in Illinois and one of only two known in the state to use Phoenix columns. A 1993 steel sub-structure was added to reinforce the central span, and the timber deck was last replaced in 1991.","period_of_significance":"1906","architect_builder":"Illinois Central Railroad, Phoenix Iron Company","architectural_style":"OTHER: King post, pony timber truss; Phoenix column","criteria":["C"],"status_note":"Carries two-way vehicular traffic, posted for 8 tons and 10 mph. A steel sub-structure was added in 1993 to shore up the bridge after an engineering assessment found decay in the timbers.","vacant_flag":false,"machine_generated":true,"model":"claude-sonnet-5-5","prompt_version":"v1.0-2026-10-29","generated_at":"2026-10-29 02:55:37.123304-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/opastorage/live/93/8936/28893693/content/electronic-records/rg-079/NPS_IL/97000383.pdf"},"photo":{"url_800":"https://nationalhistoricalregister.com/media/97000383/347afb06ca-800.webp","url_1600":"https://nationalhistoricalregister.com/media/97000383/347afb06ca-1600.webp","licence":"Public domain","author":"Run4earth at en.wikipedia","credit_html":"<a href=\"https://commons.wikimedia.org/wiki/File:Camelback_Bridge,_Normal,_Illinois.jpeg\" rel=\"noopener\">Run4earth at en.wikipedia</a>, Public domain, via Wikimedia Commons","source_page":"https://commons.wikimedia.org/wiki/File:Camelback_Bridge,_Normal,_Illinois.jpeg"},"district":null,"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/28893693","wikipedia":"https://en.wikipedia.org/wiki/Camelback_Bridge","wikidata":"https://www.wikidata.org/wiki/Q5025872"},"indexable":true,"url":"https://nationalhistoricalregister.com/illinois/mclean-county/camelback-bridge-97000383/"}