When two sides in a collective bargaining situation get to a point where meaningful progress is no longer being made, either side may request assistance from the NMB in the form of mediated negotiations. A federal mediator will be assigned to the property, and his/her job will be to get an agreement between the parties. Arbitration, on the other hand, occurs when Both sides agree to make their case to an arbitrator who will make a legally binding decision on which offer (labor or management) will be the new contract. A proffer of arbitration must be accepted by both parties, if it isn't the mediator can either continue with the mediated negotiation, send everybody home for an indeterminate amount of time (aka putting negotiations on ice), or release the parties to self help (strike, lockout, imposition of company terms).

Union reps SHOULD know the difference between the two processes.