49 C.F.R. § 234.203 Control circuits.
Title 49 - Transportation
All control circuits that affect the safe operation of a highway-rail grade crossing warning system shall operate on the fail-safe principle.
Title 49: Transportation
PART 234—GRADE CROSSING SIGNAL SYSTEM SAFETY
Subpart D—Maintenance, Inspection, and Testing
Maintenance Standards
§ 234.203 Control circuits.
