Always had this question: Why does the Pamban bridge have no steel cross beams on either side, unlike many other river bridges in India? Would it not be necessary in the case of an unfortunate derailment? Many other railway bridges - example over the river Krishna, over Ganga etc have side steel beam protection. I have also noticed this in Bangalore, where the railway line passes over a highway - the bridge section has no side protection for derailment. Is there some other safety measure already in place, like a wheel interlock?. Thanks.