The Allegheny Mountains near Altoona, PA presented a formidable challenge, as the rugged and unforgiving geography made construction of the Pennsylvania Railroad nearly insurmountable. The ingenious design of J. Edgar Thompson and the tireless work effort of hundreds of immigrants using pickaxes, shovels, and wheelbarrows culminated in the creation of the Horseshoe Curve, which swiftly became an icon of railroading. Completed in 1854, the Horseshoe Curve was the pinnacle of civil engineering for the PRR, allowing trains to traverse the mountains at a steady grade of 1.34% without the need for switchbacks. The railroad quickly became a major artery in east / west transportation, and its significance was such that during World War II, Nazi Germany sent several spies with the intent to destroy the Horseshoe Curve. The PRR held immense pride in this engineering marvel and instructed its crews to announce to passengers when they were rounding the curve, emphasizing its iconic status and remarkable achievement. Today, the Horseshoe Curve stands as an incredible icon of railroading, and it continues to host dozens of trains traversing the Norfolk Southern Pittsburgh Line on a daily basis. In this photo, a westbound Norfolk Southern intermodal train ascends the Horseshoe Curve against the backdrop of a stunning autumn sunset on October 15, 2022.