The Difference in 12 volt and 14 volt bayonet bulb

QC is not a RS priority.

You need to look at current and wattage ratings, not just voltage.

Be careful using something other than the proper lamp.  A lamp that puts out more heat can melt the locomotive's shell.

As Ace and David have already written, make certain you are using the correct style lamp.

All 14 volt bulbs are not the same. Even if they have the same shaped glass, they vary in the design of the filament, and will draw different amps, creating different amounts of heat. Over the years, I have seen a number of melted shells.

In an engine,you should use an 18 volt bulb or convert to LED lighting. As mentioned,it is not just the voltage but the wattage. 

Here is a circuit for a constant voltage LED headlamp which puts out very little heat

http://www.jcstudiosinc.com/Bl...=619&categoryId=

Dale H

Thanks guys!!! I have used 14 volt in my trains going on 7 years haven't melted anything yet. After i wrote this i thought maybe do to different watts.   

For LED lighting, it's as simple as a resistor and a diode as a rule.  If you want constant intensity, you can add a constant current source like the CL-2, but it's not necessary.  The nice thing about LED lighting is it varies a lot less until the current really drops, the current/light curve is much flatter than incandescent bulbs.

incandescent lamps are rated for voltage and wattage (brightness, current) so you can get a 12 volt bulb that is very bright  or very dim. They are also rated for hours of life time. the ones that last longer are usually more expensive. Worth it if hard to change.

   you can usually get longer life by using a slightly higher voltage bulb and if you use a lower voltage bulb you can be assured of a short life.

  Most locos use the track voltage and the track voltage varies with the speed of the train. This will effect the life also.  All IMO; Don

Thanks John and Don!!!