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 Systems236.449 C.F.R. § 236.4Interference with normal functioning of device.Last amended: 2017Year: 2026Length: 40 wordsOfficial source Cite as 49 C.F.R. § 236.4 (2026)The normal functioning of any device shall not be interfered with in testing or otherwise without first taking measures to provide for safety of train operation which depends on normal functioning of such device. [49 FR 3382, Jan. 26, 1984]Previous49 C.F.R. § 236.3Next49 C.F.R. § 236.5