49 CFR 234.1: Scope.

(a) This part prescribes minimum—

(1) Maintenance, inspection, and testing standards for highway-rail grade crossing warning systems;

(2) Standards for the reporting of failures of highway-rail grade crossing warning systems and for the actions that railroads must take when such systems malfunction;

(3) Requirements for certain identified States to update their existing State highway-rail grade crossing action plans and submit reports about the implementation of their existing plans and for the remaining States and the District of Columbia to develop State highway-rail grade crossing action plans;

(4) Requirements that certain railroads establish systems for receiving toll-free telephone calls reporting various unsafe conditions at highway-rail grade crossings and pathway grade crossings, and for taking certain actions in response to those calls; and

(5) Requirements for reporting to, and periodically updating information contained in, the U.S. DOT National Highway-Rail Crossing Inventory for highway-rail and pathway crossings.

(b) This part does not restrict a railroad from adopting and enforcing additional or more stringent requirements not inconsistent with this part.