 Upon completion of the subway, all former streetcar lines were removed from the surface streets of Downtown Pittsburgh.The line from South Hills Junction to Castle Shannon via Overbrook (now called the Overbrook Line) was first constructed by the Pittsburgh and Castle Shannon Railroad (P&CSRR) between 1872 and 1874.In 1905, Pittsburgh Railways leased the route, and between 1909 and 1910, converted it to dual gauge, retaining the existing narrow gauge for the coal hauling trains and adding the broad for passenger service using streetcars.