This Cornerstone 109' Single-Track Pratt Deck Truss Railroad Bridge kit is based on standard-design long steel bridges in use since the early 1900s by railroads from coast to coast. Deck-truss designs are in use where overhead and side clearance is a concern. It's part of the Cornerstone Engineered Bridge System and is designed to be compatible with system abutments and bridge piers and is ideal for use with WalthersTrack Code 83 Bridge Track 948-83004 or other trackage of your choice. Kit parts come molded in dark gray plastic and feature simulated steel construction.