I use standard mini Christmas tree lights all over the layout and have for over 40 years. I get old strings of lights of any voltage at the curb or trash or garage sales and cut them up to get the light bulb sockets and the bulb holders with six inch pigtails for mounting. Strings of 10 bulbs have 12 v light bulbs and strings of 20 bulbs have 7 volt bulbs. Color does not matter as the color can be scraped off to give clear. For longer strings with 2 volt bulbs, I buy replacement packs of 12 volt or 7 volt bulbs. These replacement bulbs used to appear around Christmas at Walmart, etc. at $1 for six bulbs before Christmas and 50 cents after but are rare now. I have many spares for years ago purchases post Christmas. They are available on eBay now and you may find strings of 10- 12v or 20- 7v bulbs at garage sales or thrifts.
I prefer mine Christmas lights for building lights and car lights as they draw much less current than the bigger bulbs use in post war Lionel cars and buildings.
I use them for all my building lights which run off a 12 volt ac transformer or a cheap small ac train transformer. The light pig tail wires are mounted in the ceiling of the building and hooked to the 12v light circuit with wire nuts for easy removal of the buildings as for years I had a portable layout. Now I mount them the same way to easily change out Plasticville buildings as wanted. If two lights are needed for a building or rail car I use two 7 volt bulbs in series.
I use the bulbs to add lights to passenger cars, cabooses or any car I want to light and use 12 volt bulbs and sockets for easy replacement. I run conventional control and 12 v works for my cars but if you are modern, with constant 18 v track power, you may have to wire two 12 volt bulbs in series or add a resistor.
I use the bulbs for track power indicator lights for my hidden track section. They are in a homemade signal that can be seen from the control board to show if the hidden track sections are occupied and they show the progress of the train in the hidden tunnel.
The mini Christmas tree 12v flashers light bulbs work great on water towers, microwave towers and other towers to be air craft warning lights. If the flasher light is clear not red or the needed color I use colored Sharpie pens or thin colored paint to color them.
I use one 12v mini Christmas tree light wired across my re-setable circuit breakers to indicate when tripped. When the breaker is tripped all the transformer current goes to light the bulb. I mount them below a hole cut in the control panel that is covered with red clear plastic sheet.
Charlie
