Large Scale Central

USAT classification LED diameters

Electronics Power and Sound
#1

Looking for confirmation/info on the diameter of the “infamous” “marker”/“classification” LEDs on USA Trains diesels.

I have not pulled out all the locos, but a friend told me that some of these red/green LEDs are 5mm and some are 3mm.

Does anyone have a few close by to check?

I’m going to order some green/white LEDs to accurately reflect what the prototypes did, as these were indeed class lights, not markers. (in the F units for example, the red light when running light was in the bottom of one of the headlights)

Going to be real fun since I cannot find common anode LEDs in this color, only common cathode which will require a little trickery in DCC.

Anyway all info on the F3, Geeps, PA, NW2, etc would be helpful.

Not helpful is a lecture on classification lights or other locos.

Thanks, Greg

#2

Hi Greg, I have a GP-7 opened and the headlights and markers lights are 3mm. The number boards are bulbs. The cab light is usually a 5V 5mm bulb.

I believe the other engines use the same size LEDs. On the PA and F3’s that have a single headlight it is a 5V 5mm bulb.

Have fun,

Don

#3

Thanks Don, VERY helpful!

I was remembering the 5mm, because I have been fiddling with the F3’s lately, buy my buddy said they were 3mm, and he was working with a geep…

so it all makes sense…

Greg

#4

I just checked GP38 markers are 3mm LED. Front and rear.

#5

Thanks Dan, perhaps all the geeps are the same?

Greg

#6

Greg E.

You may want to do like i did on Ho ( D/C) Engs. On marker/classification lights you can use two fiber optics and each using a LED like a Green 2mm LED and one to a Warm White LED. On the other end of the two fiber optics put together, take a hot knife to melt a flat spot with both, to look like a round flat marker light. Then just fire up the LED in the train direction with a 1,000 Resis. in series with the LED’s. Hope i explained it easy to understand. This way you have a white in rev. direction and Green in forward for a two part trains. Or if like… have it marker a White marker light in forward and in Rev. have it showing Red. If using DCC or Batt. the Fiber Optics work great to show as two colors when you choose the directon of the LED’s. I don’t think i found any Bi-LED’s the will go Green and White yet. So been using two Fiber Optics glued to LED’s and join together at other end melted to look or show as one light. Just an idea. Noel

#7

Thanks Noel, unfortunately my fleet is too large and the geeps have 4 lights so a lot of work to do the fiber optics. Clever idea though.

I have found the bicolor green white leds in 3mm and 5mm just needed to know which to buy (both it seems)

they are common cathode, so will have to add a transistor to handle this, but it’s simple…

red is not correct for class lights on santa fe by the way, markers yes, class no…

Greg

#8

Thanks Greg… Let us know where you find the 3mm and 5 mm Green and White Bi-LED’s. Kind of hope the white is a warm white and not the blue white. They may be the three wire LED’s. lol. We can with a three wire LED change Green to a Amber by injection 1/2 volt of A/C to the cir. We also on just two wire, do this to our Ho street traffic sig. before going to rev cir. to Red bi-LED. Noel

#9

http://www.lc-led.com/View/itemNumber/716

http://www.lc-led.com/View/itemNumber/712

Greg