US lawFederal (United States)RegulationsTitle 49 CFR — TransportationChapter II — FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATIONPart 236 — RULES, STANDARDS, AND INSTRUCTIONS GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCESSubpart A — Rules and Instructions: All Systems236.10449 C.F.R. § 236.104Shunt fouling circuit.Last amended: 2017Year: 2026Length: 14 wordsOfficial source Cite as 49 C.F.R. § 236.104 (2026)Shunt fouling circuit shall be inspected and tested at least once every three months.Previous49 C.F.R. § 236.103Next49 C.F.R. § 236.105