Mars Lights are signal-safety lights used in the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

and built by Mars Signal Light Company for railroad

locomotive A locomotive is a rail transport, rail vehicle that provides the motive power for a train. Traditionally, locomotives pulled trains from the front. However, Push–pull train, push–pull operation has become common, and in the pursuit for ...

s and

firefighting apparatus A firefighting apparatus (North American English) or firefighting appliance (UK English) describes any vehicle that has been customized for use during firefighting operations. These vehicles are highly customized depending on their needs and the d ...

. Mars Lights used a variety of means to cause the light to oscillate vertically, horizontally, or both, to catch the attention of motorists and pedestrians. 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 The Chicago and North Western was a Railroad classes#Class I, Class I railroad in the Midwestern United States. It was also known as the "North Western". The railroad operated more than of track at the turn of the 20th century, and over of t ...

in 1936, and Mars Lights began appearing on locomotives in the later 1930s. Tri Lite, Inc. announced its acquisition of the Mars Signal Light Company, on January 23, 1991. Tri Lite still manufactures many of the traditional Mars Lights under the Tri Lite Mars brand. The company has since updated the Mars "888" Traffic Breaker with energy-efficient

LEDs A light-emitting diode (LED) is a semiconductor device that emits light when current flows through it. Electrons in the semiconductor recombine with electron holes, releasing energy in the form of photons. The color of the light (correspo ...

replacing the earlier sealed beam halogen/incandescent lamp.

Design variations

There were many models of Mars Lights, that used several methods to oscillate the beam. Sometimes the entire lamp and assembly were moved; on other models, the reflector behind the bulb was rotated. The beam was usually oscillated in a triple eight pattern, ''i.e.'', the beam would oscillate up and down two or more times for every horizontal sweep, providing a source for the company slogan, "The Light from Mars". The beams came in a variety of shapes and colors, with some locomotives having red and white lights.

Railroad use

Many railroads used Mars lights on a variety of locomotives, both steam and diesel, from 1930s until 1990s. Prominent users were railroads such as the

Chicago and North Western The Chicago and North Western was a Class I railroad in the Midwestern United States. It was also known as the "North Western". The railroad operated more than of track at the turn of the 20th century, and over of track in seven states befor ...

Southern Pacific The Southern Pacific (or Espee from the railroad initials) was an American Class I railroad network that existed from 1865 to 1996 and operated largely in the Western United States. The system was operated by various companies under the names ...

, and Denver and Rio Grande Western. Mars Lights are no longer used on modern

rolling stock The term rolling stock in the rail transport industry refers to railway vehicles, including both powered and unpowered vehicles: for example, locomotives, Railroad car#Freight cars, freight and Passenger railroad car, passenger cars (or coaches) ...

, having been replaced by ditch lights, with the exception of some passenger carriers, such as Chicago's

Metra Metra is the primary commuter rail system in the Chicago metropolitan area serving the city of Chicago and its surrounding suburbs via the Union Pacific Railroad, BNSF Railway, and other railroads. The system operates 243 train station, stati ...

, which uses both Mars Lights (specifically on the Gallery cars) and ditch lights on their equipment. Older locomotives originally equipped with Mars Lights may still use them if fitted and still functioning.

Fire department use

Mars Lights are still used on fire fighting apparatus. The lights continue to be produced, and are available from Tri Lite / Mars, located in Chicago, Illinois. The

Los Angeles County Fire Department The Los Angeles County Fire Department (LACoFD) provides firefighting and emergency medical services for the unincorporated parts of Los Angeles County, California, as well as 59 cities through Contract city, contracting, including the city of ...

required Mars lights as a standard LACoFD warning device until the Federal Sign & Signal BeaconRay was adopted as a replacement.

Gyralite

Gyralite is a similar type of gyrating warning light formerly made by The Pyle-National Company and now by Trans-Lite, Inc. 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.

References

{{Reflist

External links