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Railroad Glass Colors and "Cobalt Blue"
|Right. Here are lenses illustrating the official RSA Colors: Top - RSA Red, Yellow, and Green
Bottom - RSA Purple, Blue and Lunar White
|Right. Here are the opposite sides of the three bottom lenses shown above, from left to right: RSA Purple, Blue and Lunar White
|Right. These three lamp's lenses, all so-called 'cobalt blue', are the very same lenses depicted above and in the same order. But they are lit and thus have very different appearances. Obviously using the term 'cobalt' for all three entails the risk of serious confusion.|
|Right. An RSA green lens is shown on the left, and an RSA blue lens is shown on the right.|
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Sent November, 2016: "In retort to your article on RSA lens colors, it is certainly nice to see such descriptive historical information in an article. So descriptive and specific I would have thought it would contain proper footnoting of sources so that interested individuals as myself could view the original source of the material. It would be nice if you could kindly contact the author or alert him to this response so these oversights can be corrected. I don't think there is a better place than Railroadiana.org to harbor such detailed historical information. But as far as terminology in use in the hobby versus manufacturing and railroad standards, I find this level of scrutiny knitpickish, unnecessary and a fair bit obsessive-compulsive. Even the author himself uses alternate "non-RSA" terminology to describe in his own words "glass roundels, globes and lenses that, properly illuminated, produce a myriad of hues from middle chrome greens through Robin's Egg blues all the way to deep violets.
Thanks for keeping up this great website and serving us fellow collectors!" [Scott N.]
Sent April, 2017: "SCOTT N., Your saying "nitpikish" doesn't direct me as to the source of your actual complaint. I then take it you were offended by my stating any use of the term "cobalt" to describe railroad signal glassware is unquestionably incorrect? You haven't been entirely clear with your complaint.
As described and illustrated in the above article, "cobalt" is useless as a descriptive when applied to railroad signal glassware. Railroad Signal Association (R.S.A.) Signal Blue, Signal Purple and Signal Lunar White are all shades of what is euphemistically referred to as "cobalt-blue" glass, but the R.S.A. colors when lit, are without question, most distinctly different.
Your personal slighting of me (with your O.C.D. reference) makes me believe "Psychological Projection" is involved here and it seems I've hit a nerve. Are you "guilty as charged" of erroneous referencing of railroad signal glass perhaps?
I'd suggest you get yourself a copy of the 1911 signal Dictionary (Simmons-Boardman, New York 1911) usually available for under ten bucks on CD ROM, often on eBay. I'd also recommend you read all of it (it is a tome!) and please attempt to find any reference to "cobalt" being used as a descriptive for railroad signal glassware. On page 384 (figures 2675-2679)are presented the precise and official R.S.A.'s names for the 6 standard signal glass colors and note: "cobalt" is no where to be found.
You might also try to find for yourself a copy of the A.A.R.'s "History & Development of Railway Signals" (A.A.R., Chicago, 1953) and read about the history of the development of railroad signal glass by Dr. William Churchill of Cornell University while at Corning Glass Works circa 1905. Again, you will not find a single reference to the term "cobalt" when applied to railroad signal glassware as well as any of the other jargon derived names of signals glass colors such as: amber, teal and cranberry. All of which are of course non-railroad terms and unfortunately remain popular with many hand lantern collectors. Specifically, "teal" was a British antique trade term for any greenish-blue glass and was first used in 1927.
Any footnoting by myself would be pointless as in all probability, you wouldn't be able to find copies of many of the works I used. The last time I used footnotes was in my Graduate Thesis. Unless professional caliber scrutinization is necessary and anticipated, it is a great deal of (unnecessary) work. The additional bibliographical material listed below will have to suffice:
"Railway Signaling", 1921, E.K. King, McGraw-Hill Book Company, Inc., New York
"The Block System of Signaling on American Railroads" 1901, B.B. Adams Railroad Gazette New York
"Automatic Block Signals and Signal Circuits" 1908, R. Scott, McGraw Publishing Co. New York
"American Practice in Block Signaling" 1891, The Railroad Gazette, New York
"The Signal Dictionary" 1908, Simmons-Boardman, New York
As well as various signal catalog dating back to the 1880's from:
The Johnson Signal Company,
The Hall Switch & Signal Company,
The Union Switch & Signal Company, and
The General Railway Signal Company
As well as the series of publications on the complete subject of railroad signals from the A.R.A., --The American Railroad Association (post 1937 known as the A.A.R., Association of American Railroads) and
The periodical "The Signal Engineer" (later "Railway Signaling") Simmons Boardman Publishing Co. 1908-1932.
Many of the sources above date back to as long ago as the 1880's and one or two publications were originally formerly from the Franklin Institute's technical library as they were deemed of "insufficient significance and obsolete" at around 100 or so years of age. You may be able to find a copy of the Union Switch and Signal 1894 catalog (one was recently offered on eBay) and learn the colors of signal glass with in it were limited to "red, green and white" specifically being mentioned ...no other color(s) being referenced by any specific name.
Further, I do sincerely doubt you've ever actually researched this subject on your own and that you're simply repeating what too many others have incorrectly told you. I'm quite certain that had you done a bit of your own research, you'd fully agree with me.