Horseshoe Curve National Historic Landmark

Horseshoe Curve was the Pennsylvania Railroad's answer to the Allegheny Mountains: chief engineer John Edgar Thomson accepted a steeper climb west of Altoona so the line could follow the Juniata River, and the great bend let one workable grade carry the rails across a valley split by two ravines. Construction began in 1850 and was done without heavy equipment — men with picks and shovels, horses and drags — filling both ravines and cutting the point of the mountain between them; the Altoona–Johnstown line opened on February 15, 1854, replacing the cumbersome Allegheny Portage Railroad. A trackside observation park leveled inside the curve in 1879 was the first ever built for viewing trains, and traffic grew enough to add a third track in 1898 and a fourth in 1900. The curve was guarded during World War II and was even a target of Nazi Germany's failed Operation Pastorius sabotage plot in June 1942. PRR K4 No. 1361 went on display in the park in 1957, the site became a National Historic Landmark on November 13, 1966, Conrail lifted one of the four tracks in 1981, and a $5.8 million renovation finished in April 1992 added the present visitor center. Norfolk Southern has owned the line since Conrail's 1999 split, and the American Society of Civil Engineers named the curve a National Historic Civil Engineering Landmark in 2004.