Getting a trim

The yard engines in the various hump yard on the Conrail system were medium horsepower six axle units, either U23Cs or SD 38s, which had good adhesion, but didnt need a lot of raw power. At Selkirk, where most of the GE power was assigned(Selkirk was known as the GE captial of the world for a time) this meant U23Cs. We see one working as trim unit in the eastbound bowl.