49 C.F.R. § 236.340 Electromechanical interlocking machine; locking between electrical and mechanical levers.
Title 49 - Transportation
In electro-mechanical interlocking machine, locking between electric and mechanical levers shall be maintained so that mechanical lever cannot be operated except when released by electric lever.
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 C—Interlocking
Rules and Instructions
§ 236.340 Electromechanical interlocking machine; locking between electrical and mechanical levers.