MBTA Orange Line's 111th anniversary
The entire original Main Line El route was eventually replaced in stages. It wasn't until 1987 when the last remnants of the original elevated tracks were finally dismantled.
The only portion of the original part of the Orange Line still in use today is in the Washington Street tunnel, which opened seven years after the line began. It was built to accommodate the El's trains, which could barely squeeze through the Tremont Street tunnel.