These kits contain all the details and interior structure found on prototype bridges, such as lateral bracing, crossbeams with knee braces, stringers, rivet plates, bridge shoes and extensive molded-in detail including rivet heads. HO Code 83 Bridge Flex-Track is included with each kit. The bridges can be modeled with square or rounded ends on the girders -- both types are found on the prototype. They can also be modeled as open-deck bridges using the "concrete" deck included in each kit. Additional Through-Girder Bridges and/or Deck Girder Bridges can be combined, along with Bridge Supports #255-80175 (all sold separately) to form longer custom bridges.