The Port Authority considered ending all Brown Line service, but this would have provided only limited savings unless the tracks and overhead wires were also decommissioned.

[6] As of February 2021, The Port Authority's newly released 25-year plan includes the possibility of reviving service on the Allentown line due to continuing growth of the neighborhood.

It provided service to the Allentown neighborhood of Pittsburgh, Pennsylvania, where dense housing and the hilly terrain make automobile transportation difficult—some area streets cannot be used at all during the winter.

It continued along Warrington in an easterly direction until turning left onto Arlington Avenue, where it followed the sharply curving street northwards, over the shoulder of Mount Washington.

At the intersection of McArdle Roadway, it swung onto private right-of-way to reach the Panhandle Bridge (also used by the Red and Blue Lines) to cross the Monongahela River and gain entry to downtown, stopping at First Avenue, Steel Plaza, and Wood Street.