Hi, I’m hoping that forum members can help me to identify this signal. I found it among a box of American Flyer items that mostly date from around 1936 (Set # 1710-RT). I haven’t been able to find a catalog refererence (name or number).
Glad I found this forum! Thanks!
Jim
I believe I have found your signal in my "Standard catalog of American flyer Trains.I found a signal that looks just like yours under wide and O-Gauge signals and crossing gates.
2005 Triangle Light The head of this 1935-39 block signal held three bulbs and on its rear was a selector switch.
Type l Green painted
Type ll Blue painted
red bulb, green bulb, clear bulb
page 311
David
Yours may not have the correct bulbs, red left, green right, clear bottom
[#welcome] to the forum
Irontooth is correct
Welcome too, to the world of Prewar American Flyer
Enjoying the World’s Greatest Hobby
Northwoods Flyer
You may be interested to know that originally green was used for approach, instead of yellow, and white was used for clear, instead of green. This signal seems to be an example of this earlier convention.
I have heard two explanations for the change: A broken glass filter on a signal head turned a stop or approach into a clear. And, as electric lights became more common, it became a nuisance to distinguish them from the signals.
The motive for choosing white for “don’t walk” and orange for “walk” seems to be to avoid confusion with the signals for vehicles. But I imagine that the use of white might also have been inspired by those early railroad signals.
Thanks! Nice to see a working model.
These things always remind me of martians! [(-D]
[#welcome] aboard!
Becky
I have one exactly like this but have no bulbs. Does anyone know what size and type it takes? Im assuming DC voltage from the center rail and ground rail? thanks!
Welcome aboard T_Mack! 
. AC if you’re running prewar American Flyer O Gauge (Narrow Gauge in Flyer catalogs) 3 rail trains. I may be wrong but in the photo above the bulbs look like 432R candelabra base screw types. I’m guessing you would want a 432R, a 432A (Amber) and a 432 G for the traditional R-Y-G. Unless you want to replace the yellow with a blue for that Martian look 
432 bulbs are likely correct. However 432 bulbs are 18V and have E10 bases which are miniature, not candelabra. All candelabra base bulbs are 120V, their base size is E12.
