An unparalleled engineering feat for its day, the inclined plane that rises above Johnstown is the steepest vehicular inclined plane in the world, traveling 502.5 vertical feet at a 71.9 percent grade up Yoder Hill. Access to the railway is via a truss bridge over Stony Creek, which flows along the base of the hill. The inclined plane was designed by Hungarian engineer Samuel Diescher, who assisted in the design of the Monongahela incline and designed the Duquesne Heights incline (see Inclines: A Trio of Diescher Inclines on p. 76), the only two still operating in Pittsburgh. He designed many other inclines throughout the United States and abroad.
Construction was prompted by the need for an escape route to high ground during floods, and for real estate profits to be made by the Cambria Iron Company from their development in Westmont ( CA22). The plane proved useful during the flood of 1936, when nearly 4,000 citizens rode it to safety after boarding it from both the bridge and the rescue boats on rising Stony Creek. The plane has twice been saved from bankruptcy by community action and has been refurbished many times by volunteers. The most recent project was a government-funded, year-long restoration of tracks, cars, and both stations in 1984 that returned the plane to its place as a major tourist attraction in Johnstown. In 2001, the wrought-iron and steel, pin-connected and riveted 232-foot-long truss bridge over Stony Creek was refurbished. The inclined plane, built so soon after the devastating flood of 1889, is a symbol of the city's resilience.