Integrated Circuit Current limiter up to 15 mA IC-334
Use this IC and a resistor between the blue lead and your 1.5 Volt 15 mA bulbs. Keep your bulbs running RIGHT no matter what the track voltage!
Control 15 mA bulbs (as in Athearn Genesis locos) with ease. Connect all the bulbs you want to light at the same time (up to 6 bulbs) together in series (in one and out the other) and connect an IC-334 and a 5.1 ohm resistor