The hills around Pittsburgh were once strewn with inclines of various sizes and shapes. These were once the most convenient way to get from the top of the surrounding hills to the city, and back up. There were inclines for pedestrian traffic, wagons and vehicles, and a couple large ones for larger cargo. Today, only two inclines remain, the Monongahela Incline (pictured) and the Duquesne Incline further down river.

The Monongahela Incline was the first passenger incline in the city, built in 1870. It spans 642 feet from Carson Street to Grandview Avenue. The landmark incline is now operated by the Port Authority and as well as being a tourist attraction it is still a much used method of transportation from Mount Washington to Station Square. In older days this was a double incline, with a passenger side and a vehicle side. The vehicle incline was removed many years ago, but the cement foundations still run the course up the slope.

Wikipedia: Monongahela Incline.