Utility Workers Union of America
AFL - CIO Local 127

Though it’s best to resolve workplace disputes at the lowest level possible – to save time and money, and to avoid uncertainty – quite often no resolution is possible by the last step of the grievance procedure.  So you may find yourself at the end of the line:  arbitration.  While each of the meetings that takes place at the various steps of the grievance procedure is sort of a mini-“day in court,” an arbitration hearing is pretty much the real thing.  An arbitrator is a neutral third party, usually an attorney, selected jointly by the employer and the union.  Professional arbitrators function much as judges do in regular courts of law.  Arbitrators swear in witnesses, rule on who can testify and on what evidence can be introduced.  The payment for the arbitrator’s services, and certain other costs associated with the process, usually are split fifty-fifty by the employer and the union.
-- Adapted from The Union Members Complete Guide, by Michael Mauer