They're not - and that's the problem.
The RMT▸ require Chiltern to employ a second safety-critical trained person on each train in passenger service., effectively doubling the staff costs for each train. The DfT» refuse to pay.
Thanks, ChrisB — this isn't aimed at you personally, and I appreciate you’re not speaking for RMT, Chiltern,
GWR▸ , etc. So the words you used may not be those used by those organisations.
That said, the phrase “the RMT require” is an interesting one and really ought to be challenged. Require on what authority? Since when do unions set operational requirements, and where are the management in this? Are the RMT funding these “requirements”, or are they simply being accepted? What about the passengers (nee customers) and taxpayers who pay for all this, do they get a say?
I get the desire to avoid industrial action, but management can’t keep deferring this indefinitely. The unions must know this argument was settled decades ago. They should call the RMT's bluff and schedule some trains, of course that is wasy for me to say.