I should hire a proofreader, I guess! Correction: The PRR is now known as the "Shippensburg Secondary", NOT the "Carlisle Secondary". Didn't catch the error til I posted. Sorry. Odd they call it that, though... tracks haven't gone to Shippensburg for 30-odd years!
This bridge is NOT abandoned. It is owned by the National Passenger Railroad Corp. (Amtrak), and is still carries a tail track on the south leg of the wye. Amtrak uses it occasionally to turn trains, individual cars, or locomotives through the wye track at "State" (the railroad name for this interlocking). How do I know? I've used it!
HISTORY: The 2d Street overpass was originally part of the Cumberland Valley Branch of the Pennsylvania Railroad. Tracks no longer go all the way across the river, but the river bridge is still under ownership and is capable of handling rail traffic should future needs require it. The line originally connected the PRR Harrisburg hub with The Reading Company at Lurgan Tower, near Shippensburg. With the advent of Conrail in 1976, the PRR and the Reading were duplicate lines following the same route. The Reading was a better route and thus kept as the through route to Hagerstown, is now known as the Lurgan Line, and owned by Norfolk Southern (NS). The PRR from Camp Hill to Carlisle is still in daily use, and the end of track now is at the west end of Carlisle near the Giant Foods distribution center. The PRR track, now known as the Carlisle Secondary and owned by NS, is accessed by an interlocking crossover from the Lurgan Line in Camp Hill. This ex-PRR trackage has been much bandied about as a possible route for future commuter rail, which would restore the connection via this overpass, to regular use. Historically, the route's main downfall was many blocks of down-the-center-of-the-street trackage in the Borough of Shippensburg, and the fact that it bisected Shippensburg State College. Until abandoned by Conrail in the late '70s, trains passing through Shippensburg, down the center of Earl Street, often cut the town in half for as much as 20 minutes.