Washington as a tunnel to transport coal from Castle Shannon, Pennsylvania to Pittsburgh.
In spite of its location above the rivers in Pittsburgh, it sustained flood damage on at least one occasion.
[3] The Pittsburgh and Castle Shannon Tunnel was closed to passenger traffic in 1880, but coal trains continued to use it until 1912.
The right of way, excluding the tunnel through the coal mine, was leased by Pittsburgh Railways in 1905, and later purchased in 1950.
[4] The right of way is part of the Pittsburgh Light Rail transportation system today, from South Hills Junction to Library, Pennsylvania.