As a practical conveyance during the horse-and-buggy era, the Monongahela Incline was one of seventeen built and operated in Pittsburgh in the last century. Of the seventeen, the Monongahela and the Duquesne are the only two remaining operating units. While the Mt. Washington Incline was known as a coal-carrying incline plane in 1854, the Monongahela Incline is probably the earliest passenger-carrying incline in the United States and has been in continuous successful service since its construction.
Incline

YearAdded:
Image Credit: Courtesy Flickr/Jason Rosenberg (CC BY 2.0)Image Caption: Monongahela InclineEra_date_from: 1870
1977

At the mountain where the Civil War's Battle Above the Clouds was waged, tourist business has thrived from the building of its first toll road (Whiteside Pike) in 1857 to present day.
YearAdded:
Image Credit: Courtesy Flickr/Duane Tate (CC BY 2.0)Image Caption: Lookout Mountain Incline RailwayEra_date_from: 1895
1991