49 C.F.R. § 236.724 Circuit, shunt fouling.
Title 49 - Transportation
The track circuit in the fouling section of a turnout, connected in multiple with the track circuit in the main track.
Title 49: Transportation
PART 236—RULES, STANDARDS, AND INSTRUCTIONS GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES
Subpart G—Definitions
§ 236.724 Circuit, shunt fouling.