You want to put signals on your layout.  Stop and think.   I was reading a very good article about signals in the DO magazine.  LIGHT BULB turned on. 

I suffer from red pimentos. To make it simple my wife has always took me what color tie to wear with my suits and dress shirts.  You know guys.

Yes I can see Yellow and Red and Green when on a rail car. Not the green that easy if in shades.  When you use LEDS in signals you are asking for trouble big time from many of your operators.  The search light signals where you use voltage to change color of signal are the worst.  No way I can tell you what color they are.  My problem is very common in white males over 45.  So if the shoe fits, speak up when you here people talking about signals. If you want them and prototype is not an issue make them three aspect signals Red Yellow Green.  This way people like me and others do not need to worry about color just the position and if they are flashing.