Allegheny Portage Railroad
The Allegheny Portage Railroad was the first railroad constructed through the Allegheny Mountains in central Pennsylvania. It operated from 1834 to 1854 as the first transportation infrastructure through the gaps of the Allegheny that connected the midwest to the eastern seaboard across the barrier range of the Allegheny Front.
Source: Wikipedia — Allegheny Portage Railroad (CC BY-SA 4.0)