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Nostalgia & History > Old Steam Headlights
Date: 09/02/12 14:07
Old Steam Headlights
I just received my copies of Edson/Vail's Locomotives of the New York Central Lines. There are a lot of photos of many different classes of steam locomotives built about the turn of the 19th/20th centuries. Some of the headlights are centered, but huge, and appear to have a small container (oil?) above them. They are circular, do not have the big surrounding boxes of the oil or kerosene fired ones. Yes, I have googled but the info there is very sparse. I don't see a dynamo on most of the engines, so I am surmising that these lights are fuel fired. Can anyone shed some light (pun intended) on these?
Date: 09/02/12 14:19
Re: Old Steam Headlights
Probably gas lamps. Gas tank looks like an extra air tank.
Date: 09/02/12 17:07
Re: Old Steam Headlights
Up to about 1890 headlights were kerosene powered. These headlight cases were almost always big rectangular, with a curved pyramid top, and a cylindrical horizontal ventilator at to top.
In the 1890's, carbide lamps were often used. These were smaller, and had two chambers, usually behind and/or below the light giving portion. The lower chamber was filled with calcium carbide crystals, the upper with water. Adjusting a valve to allow water to drip onto the crystals controlled a chemical reaction which generated acetylene gas, which burned with a bright, hot, white light.
By 1900, carbon arc lights were being used. These required an electric dynamo, similar if not identical to those used yet today on steam locos. The bottom of the headlight case contained a thick copper plate which served as one terminal of the arc, and above that was the second terminal - a carbon rod suspended from mechanism linked to a solenoid. When turned on, the current flowed thru the solenoid, then the carbon rod, jumped the arc, and to the lower copper plate. The current thru the solenoid caused it to pull the arc away from the plate, and thus the mechanism was self regulating to maintain a constant brilliance. Incidentally, streetcars also commonly used these same type of lights.
Later, of course, incandescent lights became the norm.
Note that, other than the incandescent lamp, none of these lamps are easy to turn on and off. It was common to have a sheild which could be hung over the headlight glass to hide, rather than extinguish, the light. Alternatively, the fireman could simply walk to the front of the engine and sheild the headlight with his shovel to indicate to an oncomming meet that his train was in the clear. (When in use, the carbon arc lights were so hot that the copper plate could liquify - when power was shut off, the carbon rod would drop into the liquid copper, and sort of weld itself into place making restaring problematic.)