Adding DC Ditch Lights

Model Railroader Electronics and DCC
1

Hello,

I have recently bought a https://www.walthers.com/emd-gp9-phase-2-w-chopped-nose-standard-dc-norfolk-southern-2000-black-white

I want to add ditch lights to the circuit board and have bought these:

https://rapidotrains.com/products/ho-scale/rapido-bits-ho-diesel/rapido-bits-ho-operating-ho-scale-deck-mounted-ditch-lights

Can anyone please provide some guidance?

2

Adding LEDs to a DC locomotive is difficult because of the varing voltage. The LED brightness will vary with the locomotive speed. White LEDs operate at about 3 volts and max current is 20ma. If your locomotive at full speed takes 12 volts you will need a 500Ω resistor, it will let the LED run at max current, about 20ma.

At 4 volts the same resistor will only be a couple of ma and not work at all under 3 volts.

For me an LED operating at 20ma is far too bright so using a larger resistor will drop the low voltage brightness a lot. I operate my LEDs at about 1 to 4ma and even then the 4ma is very bright.

LEDs do work on DC locomotives, just not very good with the varying votage.

Mel

My Model Railroad
http://melvineperry.blogspot.com/

Bakersfield, California

I’m beginning to realize that aging is not for wimps.

3

Thanks for the reply Mel,

I think i’ll go ahead and see how it looks.

4

Randy might steer him toward a constant-voltage board, or something with a small battery for the very small power two flashing LEDs would involve. Getting prototypical brightening and dimming ought to be built into his flasher board already.

5

I really miss Randy! Yes he would have him up and working with something simple that would work great.

Doing something like you suggested is something like I would do for myself but not try and sell it to someone else.

Mel

Modeling the early to mid 1950s SP in HO scale since 1951

My Model Railroad
http://melvineperry.blogspot.com/

Bakersfield, California

I’m beginning to realize that aging is not for wimps.

6

I just read the Walthers link the OP posted. It has a 21 plug DCC board, with constant and directional head lights.

Shouldn’t be hard to tap into what’s already there.

Unless the “Product Description” covers both DC and DCC.

I added led lights to Athearn BB’s and I don’t remember much brightness change, as you usually don’t run them at full throttle anyway.

Mike.