A grievance arbitration tribunal authorized under the Railway Labor Act (RLA) to arbitrate any minor dispute in the railroad industry.

Public Law 89-456 authorizes individual railroads and unions to jointly set up special boards of adjustment or individually to request that the National Mediation Board form an alternative grievance arbitration tribunal called a Public Law Board. The NRAB decides any cases that do not go to special boards of adjustments or public law boards as well as any appeals from those arbitration tribunals' decisions.

For more information, see Practice Note, Railway Labor Act: Overview.