49 C.F.R. § 236.564 Acknowledging time.
Title 49 - Transportation
Acknowledging time of intermittent automatic train-stop device shall be not more than 30 seconds.
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 E—Automatic Train Stop, Train Control and Cab Signal Systems
Rules and Instructions; Locomotives
§ 236.564 Acknowledging time.