If the loaded length of span in meters of a railway steel bridge carrying a single track is 6 m, then impact factor is taken as A. 0 B. 0.5 C. Between 0.5 and 1.0 D. 1.0

The correct answer is D. 1.0.

The impact factor is a factor that is used to account for the dynamic loads that are imposed on a structure by moving loads, such as trains. The impact factor is typically taken as 1.0 for railway bridges carrying a single track. This is because the dynamic loads imposed by trains are relatively small compared to the static loads.

Option A is incorrect because the impact factor is never taken as 0. This is because the dynamic loads imposed by trains will always cause some additional stress on the structure.

Option B is incorrect because the impact factor is typically taken as 1.0 for railway bridges carrying a single track.

Option C is incorrect because the impact factor is not typically taken as a value between 0.5 and 1.0 for railway bridges carrying a single track.