49 C.F.R. § 236.707 Blade, semaphore.
Title 49 - Transportation
The extended part of a semaphore arm which shows the position of the arm.
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
§ 236.707 Blade, semaphore.