# Atlas SD24 CB&Q Gyra illumination modification - advice sought



## OilValleyRy (Oct 3, 2021)

The CB&Q version has 4 lights on the nose. 2nd from the top is a red gyra light. The lens for this particular light, unlike the other three, is a very narrow stem.
However the LED board has 2 LEDs, but also only 2 wires. Meaning either both are always on or always off. Each LED illuminates 2 lenses. Well, sort of. The red Gyra actually is blocked off on the shell, but can be easily drilled out in order to illuminate it, that’s not an issue. Consequently there appears to be no way to program the Gyra light function on the Gyra only, all four would have the effect? Photos below, then questions.


































So, first question. Has anyone else modified one of these CB&Q units in this manner? Because of how the lenses are I’d be curious to know:
A, how you illuminated the Gyra light separately from the other three clear lights, and
B, how you mounted any LED replacements where that board is?

Question 2:
Is my understanding incorrect that the red lens is the Gyra effect? Perhaps the red should be solid on and the clear above it having the Gyra effect?

Because the number boards are integrated, I don’t think putting an LED in each light position is really a viable option. I’m not opposed to putting in a single red LED for lens #2. However I’ve never drilled out one of these “light blocks” and I’m unsure if it would be successful or detrimental or somehow disruptive to light flow from the top piece to the lower piece?
Any advice on modifying this in order to have the red Gyra light (2nd lens down) programmable would be appreciated.


----------



## DonR (Oct 18, 2012)

I'm not at all familiar with that loco, but your photo
seems to indicate that it is straight DC...not DCC...
thus you have only directional control of loco lighting.
If, however, the loco is DCC, there is usually a function
on the decoder to control a 2nd light, often used
for ditch lights. Consult your manual.

Don


----------



## OilValleyRy (Oct 3, 2021)

Presently the loco is DC but will be upgraded. The DCC side of the equation isn’t an issue for me. I’m more concerned about the physical modifications, or advisable course, regarding the clear plaster & single red lens.

Would both of the lights inside the Pyle housing be a Gyra light? Or just one of the two? I’m rather unfamiliar with them other than knowing the sweep pattern.


----------



## DonR (Oct 18, 2012)

If the 'gyra' light fixture has 2 side by side bulbs, the one
that I can recall seeing on a 'real' loco, the bulbs 
alternated like a crossing signal. But that was long ago.
With single bulb fixtures the beam either swept back and forth like
a searchlight or it made a circular motion.

Don


----------



## OilValleyRy (Oct 3, 2021)

It’s a vertical twin Pyle. I’ve seen video of them in operation but it’s kind of hard to tell if both lights are moving or if thats an illusion. And yeah evidently Gyralights go circular counter clockwise, MARS lights do a figure eight motion.

At any rate, I just now realized that utilizing the upper LED for the Gyra will not work, because the effect would be present in the # boards too. So…. I guess I’ll have to drill out the front, vertically, so an LED can be slipped down between the # boards and isolate any light bleed.
One would think Atlas would design that piece to be more DCC programmable friendly, considering they offer the units DCC/sound factory equipped.


----------

