Re: arc headlights and dynamos

Posted by Jim Courtney on
URL: http://c-sng-discussion-forum.254.s1.nabble.com/arc-headlights-and-dynamos-tp15165p15166.html

A question for which I've never found a good answer.

What we refer to as the arc type headlight may be nothing more than a decorative form of kerosene powered headlamps, functionally no different than the big box headlights.

The bright light produced by carbon arc headlight would need an electrical source, not sure about acetylene.

This link suggests the "dynamo" to power such devices may have been usually located in a baggage car: http://www.railroad-line.com/forum/topic.asp?TOPIC_ID=41660

The drawing suggest the dynamo was connected to a wheel axle by a belt, not requiring steam like the Pyle type generators that came along in the early 'teens.  I guess they could have been located under the tender frame or even under the cab, connected to the rear driver axle.

Still, if a small dynamo were located under the cab, where are the cables to the headlight??

Also found this info from past searches on this subject:

An arc lamp has two electrodes that cause the electricity to arc between them causing a brilliant light. We most often think of arc lights when we see a search light in the sky, but the light bulbs used in many of today’s street and parking lots are also arc lamps. Alternately, Edison’s filament lamp operated by containing the short across a carbon filament that then glows and gives off light.

Initially, Edison’s carbon filaments were too delicate to be used in railroad operations and so there was a rush to replace oil burning lamps with arc lamps. While the operational results were better than expected, there were still problems. For example, the arc headlight was so bright that it blinded the engineers of oncoming trains. Another issue was the lamp turning off when the train came to a stop in the station and the steam engine no longer drove the generator to run it. (Implies mechanical turning of a dynamo by an axle.)

Enter Robert Pierce of Indianapolis who purchased the assets of the National Electric Headlamp Company. In association with another inventor, George Pyle, Pierce developed a separate steam driven turbine that would keep an arc lamp on even when standing in the terminal. In 1896, Pyle takes over the National Electric Headlamp Company and forms the Pyle National Company. Shortly thereafter he introduces a simpler but longer lasting arc lamp along with a redesigned, more powerful, and less expensive steam turbine to drive it. It’s a huge success and in 1899 the firm shipped 472 of its new headlamp versus sales of only 175 headlamps shipped by all US railroad headlamp manufacturers the previous year.

Up to now, all arc lamps beams were broadcast on a horizontal plane. In 1902 Pyle introduces a headlamp that adds a vertical broad cast to the illumination. The new lamp proves to be visible up to 21 miles down the track. Collisions with livestock, wild animals, and wagons plummet.

Finally, in 1913, Edison introduces a tungsten filament lamp with multi-elements. Tungsten proves to be much more ductile (able to be deformed without losing toughness) and is able to take the vibrations and abuse during railroad operations. The multi-elements increase the brightness. In 1915 the Federal government passes legislation that all locomotive must have headlamps.

https://www.jacksonvilleprogress.com/opinion/mysteries-at-your-museum-about-that-light-in-the-tunnel/article_039ca488-36f3-11e9-af2e-7ba554de7ac0.html