Look, if your boss tells you to do a job that is already performed by your group in other stations you do it or face disciplinary action. If the contract says you do it when AMFA personnel are not at that station, you do it. If AMFA has struck, they are not around. You worry about any paperwork later like grivances. Now if you consider yourself unsafe to perform a dangerous duty because of lack of training you may have a case for refusal but if the company can prove you have taken approved training - it's your job when your told to do it.
Less sarcasm and more thought equal better understanding