Mars Light

Mars lights were developed by Jerry Kennelly, a Chicago firefighter who realized that oscillating lamps would benefit fire departments and railroads.

He performed an operational test with the Chicago and North Western railroad in 1936, and Mars Lights began appearing on locomotives in the later 1930s.

The company has since updated the Mars "888" Traffic Breaker with energy-efficient LEDs replacing the earlier sealed beam halogen/incandescent lamp.

The Los Angeles County Fire Department required Mars lights as a standard LACoFD warning device until the Federal Sign & Signal BeaconRay was adopted as a replacement.

[1] Gyralite is a similar type of gyrating warning light formerly made by The Pyle-National Company and now by Trans-Lite, Inc.[2] It is distinguishable from the Mars Light in that the ratio of vertical oscillations to horizontal oscillations is unitary, producing a circular or elliptical scan effect.