Old B&M charts: what aspects do the signals represent?

Here is a sample of a stereotypical B&M chart: http://www.nmro.org/samp-n-plan.jpg" onclick="window.open(this.href);return false;

I'm looking for a key for the signal masts, as the different patterns represent the different potential signals that can possibly be displayed.

The only thing I can figure out for certain is that the circles with a horizontal line through them are only capable of displaying red. The rest have seemingly endless possibilities.

EDIT: also, circles with a diagonal line from top left to bottom right are heads that can only display a red or yellow.

I have never seen a key. Have you tried asking Scott Whitney (who sells those plans/charts via NMRO)?

There is a BMRRHS bulletin that shows all this.
John, the guy in the blue car with the wing on back

The specific BMRRHS Bulletin that shows this is Volume XV, Number 2, from 1987
John, the guy in the blue car with the wing on back

Does anyone know the best way to reach out to Mr. Scott Whitney? I struck out in searching for an email or any contact information, and I struck out trying to initiate contact on FaceBook.

Also, I was unable to find B&MRRHS Bulletin XV #2 online, nor is it in the society's latest catalog (which is dated 2015 and might not even be a valid/up to date catalog).



I reached out via email to B&MRRHS for both contact information and/or the bulletin. Hopefully they'll be able to help me out, but if not, any guidance would be appreciated.

I have seen his name on the email list for the NERail group...

Hi All
The best way to reach Scott Whitney would be to buy some of his Track charts, from his webpage, National Militant Railfan Organization.
http://www.nmro.org" onclick="window.open(this.href);return false; On his page you will find an email address, in which to contact him. Pat