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 G — Definitions236.82749 C.F.R. § 236.827System, block signal.Last amended: 2017Year: 2026Length: 21 wordsOfficial source Cite as 49 C.F.R. § 236.827 (2026)A method of governing the movement of trains into or within one or more blocks by block signals or cab signals.Previous49 C.F.R. § 236.826Next49 C.F.R. § 236.828