Pittsburgh and Castle Shannon Railroad

The Pittsburgh and Castle Shannon Railroad was built in 1871 in Allegheny County, Pennsylvania, acquiring the existing Coal Hill Coal Railroad from the Pittsburgh Coal Company and adopting an unusual 3 foot 4 inch narrow gauge, which the line's own history credits as possibly the first American common carrier narrow gauge railroad. It hauled coal from Castle Shannon into Pittsburgh through a tunnel bored under Mount Washington, later adding passenger service on the same tunnel, with trains carrying passengers by day and coal at night, and it eventually ran dual gauge track so narrow gauge coal trains and wider gauge trolleys could share the route. Passenger traffic through the tunnel ended in 1880, though coal trains kept using it until 1912. Pittsburgh Railways leased the right of way in 1905, bought it outright in 1950, and the original railroad's operations ended that year; the corridor now carries part of Pittsburgh's light rail system. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/