Jerry got it.
Pre war work train set 4177 came with a pair of tandem 6" flat cars that carries a load of 12 loose rails. Being as they look like a broken piece of track to mom and dad, most got thrown away making the correct rails very scarce. My nice boxed set has only 11 of the 12 rails. I will now be able to complete it and recoup my $$$$ selling of the balance of the set.
Steve