 The resulting Stage I LRT plan achieved a comprehensive reconstruction and upgrading of the "main line" between downtown and the suburbs of Bethel Park and Upper St. Clair via Mount Lebanon and Beechview—basically following the Skybus alignment.The crowning achievement was to be a downtown subway, eliminating the trolleys' slow, street-running loop through Pittsburgh's Golden Triangle.On December 10, 1980, after receiving federal funding, the Port Authority began construction on Stage One of its first "modern" light rail/subway service, the "T", which used a former Pittsburgh Railways trolley route to connect Downtown Pittsburgh to the South Hills.