Athearn GP38-2 custom headlights

[daveheinzel333]

Hello everyone smile.gif

I just purchased my first 'real' engine- a $30 Athearn UP GP38-2. I am impressed with most of the details, but I would really enjoy trying to detail it a little more. I haven't detailed a car yet, I'm just starting out.

Anyway, I want to make realistic headlights. I can guess that I will probably need to buy some small LEDs to use in the two existing holes under the horn, but I would also like to add 2 headlights along the edge of the front walkway (as I've seen them there in protype photos).

Can anyone offer tips on how to install the 2 lower healights and also how to wire them all together? I can imagine that they can all be daisy chained to the pickups that the current light uses, but would there be a signifigant voltage difference I need to account for? I am sure that with trial and error I'll get a quick answer, but in the mean time, I thought I'd throw the question out to you all.

Thanks for the help-
Dave

http://www.daveheinzel.com/train/engines.jpg

[yankinoz]

Hi Dave - welcome to trainboard.

I don't do much work with LEDs so I can't tell you if they make them small enough to fit in the headlight openings.

I use 1.5v, 15ma, 1.2mm diameter bulbs made by Miniatronics Miniatronics's web site (https://gear.echoms.com/clients/miniatronics/shop_home.php) these stay very cool in the headlight openings, and when they are used as individual headlights, they are very effective.

You may want to use 30ma bulbs instead. These run a little bit hotter, but still are cool enough. I don't use these, because I use Digital Command Control, and want to keep the amperage as low as possible for the electronics.

Warning: You can't wire the 1.5v bulbs directly to the track voltage (12v) or they will blow (and they do that right away)

There are several options - you can use a resistor in series with the bulbs to drop the voltage (the size of the resistor depends on the amps of the bulb.) OR - and for a DC locomotive like the Athearn I think this is the best way - you can use diodes wired in parallel with the motor and wire the bulbs to the diodes - this will have a 1.5v drop to the motor (required a bit extra umph to get the loco going ) but will give you constant bulb brightness. Click here to see how it is done (http://www.mrollins.com/constant.html)

The lights on the front walkway are called ditch lights. These can be quite a challenge to wire, as the bulbs are only slightly smaller than the ditch light castings. These are made by details west - http://www.detailswest.com

Here's an Athearn SD40-2 with ditch lights, headlights and an operating rotary beacon on top. The beacon requires a rather involved circuit and the above links show you where to buy one, or how to make one. DCC decoders include the logic.

http://www.railimages.com/album/Rob%20Barker/DSCN2329.JPG