Taaj is a three-span masonry arch bridge located on km 843+900 of Iranian railway network. The bridge has two spans of 9 meters and a span of 9 meters. Arch thickness varies between 0.8 and 1.3 meters. According to maintenance records, the bridge has been rehabilitated almost 10 years ago, and is currently accomodating a single track with an allowable axle load of 22.5 tons and a permissable speed of 60 km/h. Superstructure consists of UIC60 rails, wooden sleepers, and screw fasteners. All rail joints are welded on the bridge.

Structural integrity of the bridge is controlled in SLS and ULS. Results suggest that the bridge is prone to initiation and propagation of cracks due to an axle load of 22.5 tons. Moreover, it is not capable of withstanding longitudinal or lateral earthquakes and requires retrofitting.