And thus the problem is nothing to do with maintaining existing rights, it's o do with maintaining union power.
The two types of contract was brought in at BA after they lost their state funding as a way to adapt to the new world of competition that grew over the last 20 years. Mixed Fleet have far worse contracts than Worldwide/Eurofleet, however no individual lost out.
Why should railstaff be immune from real world pressures the rest of the country faces? What makes them so special?
Now I see. You don't have something therefore I shouldn't have something. A race to the bottom led by paulweaver it seems.