[2] In 1953, the Roscoe and Donora branches were eliminated, and the trunk line to Monongahela was cut back to the current terminus in Library.

This route was designated as 35 Shannon-Library by Pittsburgh Railways Company, and redesignated as 47L Library via Overbrook by successor Port Authority in the 1980s during the Stage I reconstruction of the streetcar system into light rail.

The Overbrook corridor was reopened on June 2, 2004, following major work which included doubling of the track and elimination of 22 traditional street level trolley stops in favor of eight new LRV style stations with platforms.

The Port Authority closed five stations along the Library branch on June 25, 2012: Martin Villa, Mine 3, Lindermer, Center and Latimer.

Leaving downtown, it crosses the Monongahela River on the Panhandle Bridge, stopping at Station Square before running through the Mount Washington Transit Tunnel.

Low platform stations are not wheelchair accessible as they require passengers to climb stairs to board the light rail vehicle.