Railroad bridges of various designs principally supported by a structure comprised of rigid steel beams.
a bridge supported by trusses
a bridge composed of connected elements typically straight The Bollman Truss
A bridge having a pair of trusses for the superstructure.
A truss bridge is a bridge composed of connected elements (typically straight) which may be stressed from tension, compression, or sometimes both in response to dynamic loads. Truss bridges are one of the oldest types of modern bridges. This type of bridge structure has a fairly simple design and is particularly cheap to construct owing to its efficient use of materials.