No, we are not talking about Superman or The Hulk.

Bending the iron is an old term for throwing a switch machine.  A modern switch machine has a set of points, tapered rails that actually come to a point.  These are hinged so throwing the switch machine doesn’t bend anything.  However, switches use to be made in a style called a “stub switch”. In that design the approaching track is loose for several feet.  To change the route they would actually bend the rails to select which track the train would take.  Hence the term, “Bending the Iron”.