49 C.F.R. § 236.335 Dogs, stops and trunnions of mechanical locking.
Title 49 - Transportation
Driving pieces, dogs, stops and trunnions shall be rigidly secured to locking bars. Swing dogs shall have full and free movement. Top plates shall be maintained securely in place.
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
§ 236.335 Dogs, stops and trunnions of mechanical locking.
