A bridge nae handy.

The Forth rail bridge seen from the north bank (North Queensferry) which had hundreds of men (and women) busily doing something to it of which I'm not sure, although I seem to remember something about coating it with something (stop me if this is to technical).
It still had choo choos crossing over, but I didnt see Robert Donat running away fom the polis (movie reference, answers please).