The Lechmere Viaduct was opened in 1912 with an incline to Lechmere Square, allowing streetcars from Cambridge Street and Bridge Street to reach the Tremont Street subway. In 1922, the Boston Elevated Railway opened a prepayment transfer station at Lechmere, separating the surface streetcars from the tunnel routes. The station was served by various tunnel routes (which eventually became the Green Line); the surface streetcars were replaced by buses. Lechmere station had two platforms on opposite sides of a balloon loop, with a small storage yard inside the loop. Lechmere was the northern terminus of the Green Line until it closed for construction of the Green Line Extension project. The replacement station will be elevated on the east side of the O'Brien Highway adjacent to the North Point neighborhood.