The Cornerstone Through Plate-Girder Bridge kit is based on one of the most common North American railroad designs, typically used to cross short distances, and as approach spans for longer obstacles. In service for for decades, theyre constructed of steel sections riveted together to form girders, and are known as through types as the track passes between, rather than on top of the spans. Features include: One of the most common American railroad bridge designs Used where extra clearance is needed above highways, waterways & other railroads Fits steam-, diesel- & modern-eras Includes Risers to model as an approach span for the Single-Track Arched Pratt Truss Bridge (933-3870, sold separately) Build as single- or double-track with parts included Easily added to new or existing scenery Authentic rivets and other details Use with Cornerstone Double-Track Truss Bridge (933-3242), Bridge Pier 2-Pack (933-3880) and Bridge Abutment 2-Pack (933-3881) each sold separately - adaptable to most N Scale bridges Molded in dark gray plastic