One of the most common types of bridges for freight trains, theTruss Design Lift Bridge is a working replica of the many lift bridges that have been made over the last 100 years. This bridge uses a small handle and crankshaft to lift the center span to the top of the truss structure, allowing trolls and other vehicles to safely pass between the two ends. The kit can be mostly made without glue and taken apart for storage. Snug slot construction and accurate cutting makes this possible!