The four-year slog to carve through the Alleghenies was made possible by the hard work of Irish immigrants hired by the Pennsylvania Railroad. The Horseshoe Curve, and ultimately the new ...

Courtesy photo Irish Pennsylvania Railroad Workers operate machinery during railroad construction in the 1850s. The world famous Horseshoe Curve continues to be considered a modern marvel.

Courtesy photo This photo of the Pennsylvania Limited on the Horseshoe Curve is one of many on display ... The William H. Rau PRR Photograph Collection is owned by American Premier Underwriters ...