This is the South Hills Railcar Junction as it looked in 1906, shortly after the tunnel was built. All Port Authority traffic to the South Hills came through this tunnel and it was, and probably always will be, one of the busiest intersections in the city. For 100 years, there has been a constant stream of trolleys (now buses and light-rail cars) buzzing by on their way to Brookline, Beechview, Carrick, or numerous other destinations in the South Hills. The tunnel, built under Mount Washington, and the transportation opportunites it presented to South Hills residents was directly responsible for spurring development in these southern communities. Note the old Castle Shannon Railroad passenger train chugging along on the hillside behind the junction. Prior to 1904, this low guage railroad, once used primarily to ship coal to the city, was the best transportation alternative offered to commuters traveling from the south.