The Railway concrete bridge (type IV) was modeled on a real building. It is mainly made of 3mm plywood, and the walls, abutments’ faces and railings are made of cardboard from 0.5 to 1.4mm thick. Brick and stone walls on the abutments are laser engraved. You can build a road or a small stream under the bridge. Additionally, the bridge can be extended with additional middle sections.