They should move to as quickly as possible to an automated system, in the meantime simply sack them all and pull in other competent drivers. They could teach them to drive these trains in no time at all and negotiate a sensible wage and pensions.
We can all remember how it was that the unions totally decimated British Leyland with their stupidity.
Get serious with them and those who have lost their holidays, money and are kept from work, then it is time to take individuals to task. Ask them in person for their money back.