Mars Lights

[tree68]

MILW Trains

The Mars Light was liked by some railroads, and was also seen on a lot of fire apparatus in the 1940s-60s.

And still is.

I believe the "Mars" lights used on fire apparatus actually prescribe a series of "8's", with the up and down axis being swept several times for each horizontal sweep.

[MILW Trains]

The Mars light was an early mechanical flashing/warning light.

"A railroader had worked out the general idea…"

Actually, it was the brainchild of Chicago aerial truck (hook & ladder) driver Jerry (Jeremiah) Kennelly.

City traffic was already getting bad in the 1920s, making it increasingly dangerous and difficult for emergency vehicles to get through. Fire apparatus in this period were usually fitted with small hand-held spotlights (Chicago apparatus also carried (and still carry) small red and green forward-facing warning lamps). Kennelly realized that if he wiggled the spotlight by hand, it caught the attention of oncoming drivers. He continued his experiments into the 30s (as city traffic got worse), replacing the white lens with a red one and eventually adding a motor and gearbox so it would turn in a unique horizontal figure-8 pattern. This made the beam visible to both oncoming traffic and in rear-view mirrors, and produced a noticeable flashing effect.

Kennelly later made the acquaintance of Frank Mars, head of the famed Chicago candy company, who liked what he saw and provided both financial and engineering help, which his wife continued after Mars' death in 1933. This is where the Mars in Mars Light came from.

The first railroad tests came in 1936 on the CNW, but used a blue lens, as red would be misinterpreted as a stop signal. This was later replaced with a standard white lens.

"The original "Green Diamond" had a light that pointed straight up as an attention getter. The Pacifics assigned to the original C&NW "400" also had a headlight angled upward at a 45-degree angle."

As high-speed trains were introduced, there was a lot of concern that motorists would never see or hear them coming especially at night – humans have a hard time judging the speed of anything bigger than we are coming at us. These earlier warning lights were fixed searchlights, positioned to point straight up or at an angle so they would not blind oncoming train crews or motorists, however the powerful light beam did make them easier to see at night. Diesels, being much quieter and nearly smokeless, were also that much harder to see by day and railroads began looking at ways to make them more visible.

The Mars Light was liked by some railroads, and was also seen on a lot of fire apparatus in the 1940s-60s.
 

Lance Burton

[lonewoof]

 The gearing is really not all that complicated: to get a "figure 8" all that's needed is two cams, or cranks, to move the lamp and reflector horizontally and vertically, with a 2-1 speed reduction between the two cranks.

I have on my project list to build one; it would be very crude, and unfortunately not anywhere NEAR HO scale, but at least it would show the sweeping pattern.

 /Lone

 

[ALCO Ed]

Thanks for the welcome

 Thanks for this info.  It must have an interesting gear system that allows a figure 8

[wjstix]

Interstingly it was the same "Mars" who made Mars candy.  A railroader had worked out the general idea and he and Mr.Mars got it working and patented. 

[CSSHEGEWISCH]

Mars is actually a trademark.  That firm makes all sorts of signal lights including light bars for squad cars.  Pyle National also made signal lights for railroads under the Gyralite name.

That being said, signal lights revolved in either a figure-eight or circular pattern.  The original "Green Diamond" had a light that pointed straight up as an attention getter.  The Pacifics assigned to the original C&NW "400" also had a headlight angled upward at a 45-degree angle.

[Deggesty]

ALCO Ed

Hi all.  I've heard about these lights but what are they?

Thanks 

Welcome to the Forums. We look forward to sharing the knowledge that you and the rest of us have picked up here and there as we have pursued our interest in railroading.

As to Mars lights, they were lights that were mounted on the front and/or rear of trains and usually swept around in a figure eight pattern. The idea was that the moving light would attract more attention than a light that shone steadily in one direction. The light on the rear of a train shone red at all times, and the light at the front was usually clear, but a red lens could drop into the beam if the tran had to stop suddenly.

[ALCO Ed]

Hi all.  I've heard about these lights but what are they?

Thanks