Lionel 617 Flying Yankee - Handrail parts ?

I restored one.  Don't know part # but that is a handrail and the backing plate that goes on the inside to hold it in place.  Go to a prewar parts supplier and they should have replacement; however, as I found out prewar parts are hard to come by.  I believe you are in luck that is a common part.  Also,  try flea Bay  Trainz and other parts people often have listings just search 616 , the engine #.

Art