The engines I have received from Sunset were wrapped with a protective tissue paper then stretch wrapped on to a full length board that had grooves milled in the board for the flanges. The full length board would keep the engine from sliding back and forth. Then the engine on the board was set into a box with individually placed firm foam blocks. Also there was a foam floor and a foam lid inside the factory box.
Must have received three dozen Sunset engines over the years with zero damage. One electric problem which was resolved on the first phone call.