Does anyone know the specific differences between Kerosene and Signal Oil?

A quick Google review basically says that Signal Oil is less viscous and hotter burning, but any idea to the actual chemistry?

Thanks in advance,

Matt Bumgarner

.

Start at page 85.
https://www.google.com/books/edition/NB ... frontcover
A lot of railroads adopted Bureau of Mines standards if you want to hunt them down.

Water-White Kerosene, Long-Time Burning Signal Oil, Mineral Seal Oil and 300-Degree Oil are all paraffin derived. As far as I can decipher, Long-Time Burning is a more refined version of Water-White Kerosene. MSO and 300 Deg oils were used almost exclusively for passenger car lighting. They wanted the best light while reducing odor and smoke but were not going to spend the higher price for burning in lanterns, semaphores or headlights. At least one current supplier of MSO describes it as "Water White". Is that the same as W-W Kerosene? I have no idea. Here is a link to an NBS publication in which many railroads state the standards they use. To find the actual text of individual railroad standards may take some digging.
https://www.google.com/books/edition/Na ... frontcover

Signal oil was animal tallow based, kerosine replaced it. Before signal oil, there was whale oil.

My understanding was that signal oil was lamp oil -- chosen to minimize sooting and, peripherally, bad smells.

If you are wondering about the chemistry, reflect on why the 'cetane' in diesel-fuel rating is named what it is.

Kerosene is 'rock-oil' petroleum based, rather than animal0-based, and it would follow that fractionally distilling some grades of feedstock carefully would produce a useful range of fractions that would not 'coke' or soot. Even a little sooting would impair signal safety... and many grades of kerosene soot remarkably heavily.

And to further complicate things, when I was little... there was a gas station not far from where I lived that had a pump separate from the gas pumps that was labeled "coal oil".

I've heard the phrase "coal oil lamp".... before I ever heard of a "kerosene lamp". I'd say that is one of those lamps with the wide cotton wick that people keep around for possible electric outage, but most often for decor. They're about useless on the light output scale.... left in the dust by the Aladdin.

Coal oil was the original incarnation of kerosene and was actually distilled from coal in 1846. Within 10 years, chemists figured out how to produce kerosene from oil. Whale oil was already about done. Between 1864 and 1867, the U. S. Lighthouse Board switched to Lard then kerosene by 1877. According to the Digest of Proceedings of the Railway Signal Association, 1895-1905, Mr. Ames of the North Shore had switched all lighting to Lighthouse kerosene to keep things standard. Conversely, many roads used long-time burn for all types of illumination except headlights owing to the amount of labor saved in maintenance of the lamps. I learned that the MSO and 300 Degree used for passenger train lighting was due to the higher flash point. It was deemed less likely to burn coaches down. It seems the differences in all of these fuels were in the following: Saybolt number, flash point, sulphur content, distillation end point temperature and cloud point temperature. Fascinating reading on early signal issues can be found here: https://www.google.com/books/edition/Di ... =1&bsq=oil
You can compare grades of kerosene here starting on page 4: https://www.google.com/books/edition/Un ... frontcover

I see the 300 degree oil has a flash point of no lower than 250 degrees F. While the other kerosene oils are around 115 or 140 degrees F.

After my own research at the SRC, we came up with the following as an acceptable recipe for signal oil: eighty (80%) percent white kerosene, eighteen (18%) percent 99.9 coal oil (paraffin), two (2%) percent camphor. The camphor is added for brilliance.

These days, I drive a desk and am fairly removed from operations, save the extra board. I don't know whether or not we are still using this in our markers or not.

Your mileage may vary