This train paper model is designed by schaalbouw. The CHD was the 'standard' freight wagon of the Dutch Railways (Nederlandse Spoorwegen)in the steam era. This wagon was replaced in the 50's after the introduction of the standardized UIC freight wagon.
The model is designed to be printed on 160 grams waterresistant photopaper. Additionally some cardstock is needed (0,5mm thick and optionally 1 mm to reenforce the sides). A printable rear side is supplied. When properly alligned this rear side colours the back side of the parts which are visible on both sides. You can download this papercraft from here: Train Paper model: Freight wagon CHD free download