Mount Washington Transit Tunnel is an important public transportation link in Pittsburgh, Pennsylvania, United States. The approximately 3500ft tunnel connects Station Square to South Hills Junction, and is used only by Pittsburgh Light Rail cars and buses of the Port Authority of Allegheny County.HistoryThe tunnel was built by Booth and Flinn for Pittsburgh Railways to overcome the barrier of Mount Washington to the development of electric streetcar services to points south. Excavation was started October 6, 1902, and the tunnel was officially opened December 1, 1904. The tunnel was paved around the rails to allow for joint use by bus and trolley traffic in 1973.The Transit tunnel is located almost in line with the Pittsburgh and Castle Shannon Tunnel, which was at a much higher elevation. That tunnel was originally a coal mine accessed from the top of an incline on the river side. It was later opened at the back and used to run through to other coal mines in the Saw Mill Run valley. The Pittsburgh and Castle Shannon Railroad operated passenger service through the tunnel from 1873 until 1892, after which passengers journeyed instead via the new Castle Shannon Incline, while coal trains continued to use the old route through the tunnel. From 1909 the main passenger service became Pittsburgh Railways streetcars running from the Transit Tunnel into the Castle Shannon route at South Hills Junction. Because of the related nature of the two tunnels, an urban legend persists that the Transit Tunnel was originally a coal mine.
