The bridge on Km 482+000 of Iranian railway network, also known as 'S' bridge, is an 80 years old stone masonry arch bridge. The bridge consists of three long spans of 36m, and seven spans of 8m, with a total length of 270 meters. It accomodates a single track with a permissable axle load of 20 tons. The bridge is situated in a complex curved section of the track with a radius of 250 meters, from which it inherited its name. Track's superstructure consists of U33 rails, steel sleepers, and fixed fasteners. Maximum operational speed of the bridge is 60 Km/h.

Summary of results:

The bridge has been controlled in serviceability limit state for three live load patterns. It is concluded that although eccentricity of the center of compression does not exceed thresholds in any of the spans, compressive tensions in mid-spans exceed the allowable values by almost 40%.