This is the N Scale Low Boy Trestle Laser-Cut Wood Kit by Bar Mills.
Now your right-of-way can cross lowlands, wetlands, hilly terrain, streams or other similar obstacles quickly and easily. This modular kit is typical of trestles found along just about every American rail line. The versatile design lends itself to easy customizing for other purposes, such as a dockside pier or unloading ramp for a coal dealer. When assembled, the model is about 4" 10cm long but each section is slotted so you can easily combine several kits to build a longer structure. All parts are laser-cut and notched to speed assembly.