Well i have been designing power supplies for railroad signals and they range around 50$ for a good one that will light up 3 lights. These power supply is made to turn on and off the searchlights and with 2 easy switches you can change the 3 different colors. It beats opening the signal case to swap wires. Searchlights are the hardest because you have to use the DC to change the directions of the motor but ive done it the easiest way. If your intrested please email me and let me know what kind of signal you want and ill get you a picture. Thanks!