Hi Grumpy,
I'm not sure I'm seeing what you are ? all I can see is the split in the drive roller and nothing on the rear rail flange at all.
As Pauline said, please explain LOL !
I feel that this is the perfect example where the gusset repair method would be the best and then groove out the existing fractures and zap them up with a TIG. Again this really is a job for a qualified tradesman and not a back yard operator.
Cheers,
BB