|
It is a very old lower quadrant signal, when there were only two aspects displayed. In those days, red was stop and white was clear. So, when stop was displayed the red lens covered the white light. This was changed because it was not "fail safe". If the red lens was broken or missing at night, a false clear would be shown. It took a lot of research to come up with a lens that would show green when the light from a kerosene lamp came though it. By the way, it is a shade of blue-green, more blue than green! On Friday, January 31, 2014 11:09 AM, GENE TACEY <taceys@gpcom.net> wrote: Group, Found this in an old photo, does anyone know what this kind of signal was used for? It has a single arm and what appears to be a weight opposite of the arm. Gene Tacey  |