I think they are designated as “Type G Signals”; they are the ones with the three lights set in a triangular pattern on the signal head.
Whatever they are called somewhere or another in my travels I encountered in the hobby press (physical) specifications for these signals. I just went through nearly half the “signal” keyword results on the index without identifying anything specified for “Type G”–or any other “Type” for that matter. These specs may be incorporated into the body of another article.
Can some benevolent soul out there either point me to where I can find these specs in the hobby press or give me the specs for both the signal head and the size of the color indicators.
I’m not sure if you are just interested in signal information or actually want to model them. If you’re looking for models, Atlas has a line of Type G signals in both HO and N scales:
Atlas Type G Signals HO
Atlas Type G Signals N
Not familiar at all with the B&O, but I think you might be thinking of the “position light” signals that B&O used. Like these Tomar HO models (scroll down to the B&O section):
Tomar Signals
I know for sure that Southern Pacific used the Type G signal as I’ve seen them passing by on the Coast Starlight. Other roads also used the Type G, but in the Southern California I have only seen them on former Southern Pacific lines.
B&O signals are CPL’s. That is, Color Position Light signals. Think PRR without the center light and the two vertical lights are green, the two horizontal lights are red, and the two diagonal lights are yellow.
The New Your Central uses type G signals, and searching for New Your Central Signals should provide you with some information. As different RR’s use different types of signals, the type G may have the colors in different positions depending on what RR used them.
Here is a link for a good signal site that also contains other signal links:
http://www.railroadsignals.us/