{"nrhp_refnum":"66000647","name":"Horseshoe Curve","other_names":[],"category":"structure","location":{"address":"5 mi. W of Altoona on PA 193","address_restricted":false,"city":"Altoona","county":"Blair County","state":"PA","lat":40.49753181650004,"lon":-78.48612984229615,"geom_source":"nps_gis"},"listed_date":"1966-11-13","is_nhl":true,"nhl_designated_date":"1966-11-13","areas_of_significance":["Engineering","Transportation"],"significance_levels":["national"],"summary":{"what_it_is":"Horseshoe Curve is a railroad curve of the Pennsylvania Railroad's main line in Logan's Narrows, about five miles southwest of Altoona in Blair County, Pennsylvania. It was built in 1852-54 and is 2,375 feet long with a central angle of 220 degrees.","why_significant":"The nomination argues the curve is one of the most remarkable examples of antebellum railroad engineering and construction in the United States. Its completion joined the eastern and western divisions of the Pennsylvania Railroad, contributing to that railroad's rise. The engineering solved a steep-grade problem by filling two ravines and cutting into a mountain face.","narrative":"Built between 1852 and 1854 in Logan's Narrows, about five miles southwest of Altoona, Pennsylvania, Horseshoe Curve is a 2,375-foot railroad curve with a central angle of 220 degrees. Pennsylvania Railroad engineers faced a dead-end valley and reached the far ridge by filling Kittanning Run, cutting into the face of Kittanning Point, and filling Glenwhite Run. This lowered the grade on the eastern approach to the Allegheny summit to a practical level. The line was placed in service in 1854 with two tracks, and the completed curve linked the railroad's eastern and western divisions, helping establish the Pennsylvania Railroad as a leading carrier. The curve was later expanded to four tracks, and the rails were transposed to spread wear. It is regarded as one of the outstanding examples of antebellum railroad engineering in the country.","period_of_significance":"1852-54","architect_builder":null,"architectural_style":null,"criteria":[],"status_note":"The curve has been enlarged from two to four tracks and remains a vital part of the Penn Central Railroad; a steam locomotive and a caboose are on permanent display at a nearby park.","vacant_flag":false,"machine_generated":true,"model":"claude-haiku-5-5","prompt_version":"v1.1-2026-10-29","generated_at":"2026-10-29 17:11:29.415269-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/lz/electronic-records/rg-079/NPS_PA/66000647_NHL.pdf"},"photo":{"url_800":"https://nationalhistoricalregister.com/media/66000647/400f5ba6e8-800.webp","url_1600":"https://nationalhistoricalregister.com/media/66000647/400f5ba6e8-1600.webp","licence":"Public domain","author":"Center for Earth Resources Observation and Science, United States Geological Survey","credit_html":"<a href=\"https://commons.wikimedia.org/wiki/File:Horseshoe_Curve_aerial_photo,_March_2006.jpg\" rel=\"noopener\">Center for Earth Resources Observation and Science, United States Geological Survey</a>, Public domain, via Wikimedia Commons","source_page":"https://commons.wikimedia.org/wiki/File:Horseshoe_Curve_aerial_photo,_March_2006.jpg"},"district":null,"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/71994127","wikipedia":"https://en.wikipedia.org/wiki/Horseshoe_Curve_(Pennsylvania)","wikidata":"https://www.wikidata.org/wiki/Q42730"},"indexable":true,"url":"https://nationalhistoricalregister.com/pennsylvania/blair-county/horseshoe-curve-66000647/"}