Mink, the sleigh in those pictures is the one I replaced with the steel runner sleigh. I had the same problem with the front bunk breaking. I had replaced it three or four times.
I had the same misconceptions as many folks had about the steel sleighs. They freeze down too fast, they pull hard, etc. All bologny. They work every bit as well if not better. You don’t have to treat the runners and all you have to do to replace the shoes is scarf a few welds and put new plate on.