Here is a photo of a PRR X54 plugdoor boxcar that I kitbashed from a 50' Branchline plug door car. Basically I cut about 5' from each end, deepened the sidesills, and then added a Plano running board on a shortened Moloco Roof.
I painted the car with long out of production Polly Scale Italian Camouflage Brown and then lettered it with my own custom printed PRR decals. K4 Decals now has a PRR X54 set available. The Railroad Museum of PA has a restored X54 inside and that is where I went to get the info for this car.
This is my fourth X54 that I have kitbashed......this car sat unweathered for a number of years before I finally got around to it.