I’ve been interested in adding a little more detail to some of my old HO steam locos, and part of that includes changing out the headlights on some of them. I made myself a 14” Pyle-National headlight in a 3D modeling program and printed it out (I’m trying to stick to a budget). The print turned out just fine; it has a little cavity inside which could (hopefully) hold a light of some kind, but now I’m having trouble figuring out what I can do to get it lit, if at all possible.
I read somewhere that a small SMD-type LED would be a good lighting option for a headlight (and it seems like some of them out there should be plenty small enough to fit inside), but I’m still trying to figure out whether or not such a lighting arrangement would actually work in some or all of my locos. Some of them include:
A Bachmann DCC-Ready Niagara 4-8-4
An Athearn Genesis 2-8-2 (DCC ready??)
Two old metal Mantua engines, an 0-4-0 and 4-6-2 (one or both may get remotored)
A newer Bachmann plain-DC 0-6-0
Model Power 0-4-0T
(As a note, I would prefer not to switch to DCC).
The trouble I’m running into is that the information I’ve searched for hasn’t led me to a definite conclusion. From what I’ve gathered:
-Some people say they simply use an LED in combination with a 1000-Ohm resistor, and voila—they have an LED in their loco. A few others have said they tried different resistors (i.e. 2200], but for the most part it seems the 1-k-Ohm resistor is the rule of thumb for them.
-Some others have said that LED’s won’t even work in a DC loco just because of the differences between DC and DCC. One thing is that incandescent bulbs run on voltage, while LED’s run on current. Another thing is the amount of voltage needed for a
Rather than talk the OP out of DCC, I’m going to suggest that as a given.
LED’s have a polarity, meaning if it were as simple as adding a resisitor, you would only have light going foward but not in reverse, in DC.
LED’s “live” in a much narrower voltage range than a filament lamp. The resisitor solves the problem of high voltage, but at low voltage, nothing happens.
This issue comes up with lighting passenger cars with DC and LED’s. This may help define your problem
I would say it depends on the amount of realism you desire. Simple LED lighting is easy as Henry suggested.
A simple LED in series with a 1000Ω resistor will give you light in one direction. Using a bridge rectifier (DB107) with a 1KΩ series resistor will give you light in both directions.
The LED is a current device and more voltage means more current or less voltage means less current. Fluctuating brightness with speed. Operating on DC the track voltage goes from 0 to roughly 12 volts. A white LED start voltage is roughly 2.8 volts (very dim), with a 1KΩ resistor the start voltage is a bit over 3.3 volts and gradually brightens as the voltage or speed of the locomotive increases.
There are ways to help the LED brightness to stabilize but only at a higher voltage than the locomotive begins moving on DC.
A battery operated LED is one way to have constant brightness. I use small rechargeable Coin Cells for LED power in some of my old timer coaches. My coaches are towed by Shays that normal
