I saw some of those wheat bulbs on eBay and was wondering if that would work. I will go ahead and get some.I replaced one of these years ago with a "grain of wheat bulb," a little bulb with two leads. I still have a box of them somewhere. Maybe you could use an LED.
Thant was a great video, Thank You.Watch this YouTube video from "Larry the DCC Guy" on how to install a tiny surface mount led bulb in a locomotive. You will need a resistor for the led otherwise it will burnout as soon as you give it power. The led that he got from ebay comes with a resistor.