Yes, I am aware the NMB has programs they have developed to assist them in their mission.
The pertinent part of that mission in this discussion is;
“The prompt and orderly resolution of disputes arising out of the negotiation of new or revised collective bargaining agreements.”
And Yes, the RLA provides protection but does not provide any orders to the NMB or any one else that if in fact a genuine impasse exists between the parties, they are not to be released to self help.
Yes the RLA is the guidance and the NMB is the muscle, no doubt about that. Under the RLA the requirement is to conduct mediation or declare an impasse, they are not directed to settle the issue(s).
They exist to assist the parties in resolution.
Importantly, if your quote above (beginning with Pursuant) exists as a stand alone statement representing the complete definition of the purpose of the NMB then there may just as well be an edict to outlaw strikes altogether. For them to meet a regulatory dictate to avoid any and all interruption to commerce there would be no other way.
The intent of the NMB was not and can not be to usurp the rights of labor, they have just as much final responsibilty to declare an impasse, if one truly exists, as they do to determine a possible future resolution.
The reason the PEB and /or possible congressional interjection exists is to override the rights of (the individual) labor, NOT the NMB.
I don’t believe we are subject to any “rules” that abrogate our rights and I don’t believe that allowing them to delay these negotiations in to multiple years without some union and individual lobbying pointing out the lack of reasonable success with their programs (as you quote above) they presume to force upon you (us) and failure to act in good faith to the benefit of the very people they have been relegated to serve.

I appreciate a different take on this and haven’t had to think it through in many years. Evidently some don’t have that same appreciation.