Mount Washington Transit Tunnel

The Mount Washington Transit Tunnel is a tunnel for buses and light rail trains under Mount Washington in Pittsburgh, Pennsylvania. The Mount Washington Transit Tunnel is a central component of the Pittsburgh public transit system operated by Pittsburgh Regional Transit, providing a direct connection between Downtown Pittsburgh and the South Hills suburbs. The tunnel was built for the trolley services of Pittsburgh Railways, the predecessor of the modern-day Pittsburgh Light Rail system, and has been used exclusively for public transit since its construction. The tunnel, formerly known as the Mount Washington Trolley Tunnel, opened for trolleys in 1904, and was converted to a shared rail-bus tunnel in 1973. It has been the only transit-only tunnel shared by rail and buses since 2019, when the Downtown Seattle Transit Tunnel closed to buses. The construction of the Mount Washington Transit Tunnel was instrumental in the development of the South Hills, as it shortened travel times to Downtown Pittsburgh significantly. Today, the tunnel still provides a significant time savings for transit services; the alternate surface route for light rail trains, the former Brown Line, adds over 8 minutes of travel time compared to the tunnel.

Tunnel data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).