I found this postcard, an uncolored photograph without attribution of the photographer, in an antique shop in Columbia, PA.

Historians in the Facebook Group, “Trolleys, Trains, and Transportation of Lancaster County” provided additional information.

“The Columbia and Port Deposit Branch of the PRR was called the Port Line before it was re-named the Port Road after electrification in 1939. This particular view appears to be right west of where the present PECO Muddy Run pumping/generation plant is located. The tall hillside is the site of the Susquehannock State Park lookout area up top.”

“Port Interlocking was at Washington Boro. A&S (Atglen & Susquehanna) took the high line over two high trestle bridges and went thru Quarryville on it’s way to Atglen and Parkesburg. It’s now a rail trail.

The C&PD RR continued on the low-line to Port Deposit. Later, it was extended a few miles to Perryville to join Amtrak’s Northeast Corridor. Today, Norfolk Southern runs freight on that line between Enola Yard (Harrisburg) and Baltimore. It’s runtimes are limited to evening and over night because of Amtrak.”

“The C&PD has run to Perryville since the 1800s. The Octarara Branch ran from WAWA through Oxford to ROCK interlocking on the C&PD to allow passenger trains access to Perryville. This service ceased in the 1950s.There is also the Aiken Branch from the Port Road to the Philadelphia-Balimore CSX line at CP AIKENS. This might be what you are thinking of.”