Back in 1982, in the offices of the Tidewater Grain Company, of Philadelphia, was a large photo of the PRR Girard Point Grain Elevator in the 1950s, all 12 tracks were loaded with BCK Boxcars loaded with export grain. One of many artifacts I regret not liberating.
The Buffalo Creek was a jointly owned terminal company that served the Grain elevators along the Buffalo grain front. Back in the day, most grain moved in box cars. The Buffalo Creek was hurt by Unit Train movement of grain directly from the prairie to tidewater in Unit trains, that cut out intermediate transloading and middlemen. Also, most of the joint owners, became part of Conrail.
Used to see BCK Box cars at Scott Paper, Chester, PA (PRR/PC-RDG), as they were clean cars for paper loading, during the grain off season.