wigwag

Framed by the pulsing wig-wag lights the painted the stone walls and arched windows of the front of the Gallatin Gateway Inn in vivid reds and blues, Cody Hoyt tossed the duffel he'd saved into the back of his Ford.

The wigwag is used for polishing the shoulders of pinions, pinion leaves, staffs and pivots, and for numerous other operations. […] These tools are used extensively in all the American watch factories.

Some vehicles with air brakes also use a wigwag low pressure indicator. This is mounted above the windshield. If the air pressure drops below 60 psi, the signal arm will drop down across the windshield. You can't reset it (push it back out of view) until air pressure is brought above 60 psi. Don't operate the vehicle with the signal arm lever down.

One of the first standard types of automated visual grade-crossing warning was the automated flagman, a signal commonly known as a "wigwag." According to Santa Fe documents, the wigwag was adopted as a standard crossing device by the American Railway Association in 1923. A standard wigwag is actuated by a track circuit and consists of a paddle with a red lamp that gracefully swings back and forth in a horizontal pattern when a train approaches. A wigwag is usually accompanied by a bell.

Boy Scouts and others interested in visual signaling can practice indoors with this miniature wigwag sender.