Author Topic: USA Trains GP38-2 RailPro Install and Lights  (Read 892 times)


  • Brakeman
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USA Trains GP38-2 RailPro Install and Lights
« on: May 07, 2020, 11:28:53 PM »
Hello everyone!

I'm attempting to install a RailPro + Battery in my g-scale USA Trains GP38-2 and having trouble with the lights and Smoke generators.  After working on it for 3 hours... I decided to Google for 2 more hours and found this form.  Hoping someone will be familiar with USA trains and RailPro installs.

On this model there are circuit boards for each set of lights.

The rear has 1 circuit board with 3 sets of LED's (6 total, 2 for the light, 2 for the number plate, and 2 for the direction lights which can be green/red).
The rear has 4 wires total and supplying power to different combinations of wires make different combos of lights.  I was able to get just the headlight on, or just the number plates on, and lastly I could get the direction lights to be green or red depending on how I hook them up.

The front has 1 circuit board with 1 set of LED's (2 total for the direction lights - Red/Green)
Same here - depending on how I hook these up they can be red or green.

The cab has 1 circuit board with cab light and front headlight and number plates.
Also same - depending on how you hook up the wires, just cab, or just headlight, or just number plates.

Lastly, the smoke module needs power, but I don't see any info on how to hook this up.  I might not even hook this up if it drains power faster.  If not, I wouldn't mind getting smoke working.

I'll be doing a few more engines soon, so any help with these USA trains will be much appreciated!!


  • Signalman (Global Mod)
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Re: USA Trains GP38-2 RailPro Install and Lights
« Reply #1 on: May 08, 2020, 12:31:29 PM »
Welcome mojoAustin.

We do have one or two large scale modellers here but I haven't seen them post in a while. The rest of us will be pretty clueless on working with the large scale stuff. That said, I'll try to be helpful...

Ok, so without good sized pics of the circuit boards it's a bit hard to see how they work. I did find some pics of them on USA Trains spare parts page but of course they are small and don't show much. From the sounds of your description if you wanted one for one control (one set of lights per function output) this is likely more outputs than the LM has, which is 6. Are any of these light effects changed by the slide switches? eg the red/green changed by a slide switch?

It looks like from the small PCB pics on USA Trains website that the smoke unit has it's own circuitry to power it so it should be nothing more than to hook it up to a function output (so you have control to turn it on and off). That obviously take away an output for lighting.

- Tim

Brian W.

  • Fireman
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Re: USA Trains GP38-2 RailPro Install and Lights
« Reply #2 on: May 11, 2020, 11:02:01 PM »
Hi mojoAustin,

I just installed RP in my USA F3A & B. They had two lighting boards one for the front and one for the rear, I removed both. I kept the USA main power board to power the smoke board and smoke unit as they draw so much power.I replaced the lighting with LED's using CL2N3-G LED Drivers instead of resistors. the number boards and cab light were wired in parallel with one driver and the headlights in parallel with another LED driver. The reverse light was wired with it's own driver. The cathodes were wired to the respective outputs on the RP {you chose which ones to use}. I've had no problems with lighting control or LED's burning out. I'm running on track power, but battery power would be not any different.

For reference on LED driver check,

 Also check out Gregs site for more tips on G scale mods,

I hope this helps!

« Last Edit: May 12, 2020, 06:30:53 AM by William Brillinger »


  • Brakeman
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Re: USA Trains GP38-2 RailPro Install and Lights
« Reply #3 on: May 12, 2020, 10:36:30 AM »
Thank you both so much for the reply!

I figured I'd be replacing the LED's as well, and this is surely the route I'll be taking it seems.  I did find a way to wire up the front headlight, back headlight, with the number plates on as well, but I'm a sucker for perfection and will want to have the red/green etc... so I will just replace the LED's like Brian W. did.

Thank you again!  Very helpful!


  • Fireman
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Re: USA Trains GP38-2 RailPro Install and Lights
« Reply #4 on: May 13, 2020, 05:30:28 PM »
Interesting, I am just starting the same install.  I have 3 USAT GP-38s that are waiting for the RPs to arrive.  LEDs are coming w the RP units.  Being my first installs, I've been wondering how the lights wiring would go.  Thanx for the post, links and the replies.  All will be helpful.  I took pics of the forward number-boards board, but I haven't been able to post them here.