The 47D was the last line in the city of Pittsburgh, Pennsylvania to be used solely for PCC streetcars. It originally was part of an interurban trolley line that ran from Pittsburgh to Washington, PA until 1953, when the service was cut back to the Allegheny County border at Drake and all trolleys turned using the newly constructed loop, situated below the trestle. The line to Drake became part of the 36 Shannon-Drake until the 1980s. After the 1993 closure of the Overbrook route the service became a shuttle between Castle Shannon and Drake and was renumbered 47D Drake shuttle. The line closed on September 4, 1999.
As of July 2014[update], most of the Drake Line still exists. The stretch of track from the Drake Loop to the "S" curve near the former Walthers stop was removed not long after the line was discontinued. When the Authority took delivery of new LRVs for use on the rebuilt Overbrook line in 2004, the new cars were tested on the Drake line prior to entering revenue service.
During the final years of operation, three PCCs were used with a fourth kept as reserve. Car #4004 was donated to the Pennsylvania Trolley Museum where it has become part of a collection of historic streetcars and trolleys from all across the United States and other nations. San Francisco MUNI acquired #4008 and #4009 in an internet auction in 2002 for $5,000 each. However, they are low on the priority list for a return to service as they need to be re-gaged and differ significantly from other MUNI PCCs.