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Substituting LEDs for headlight bulbs

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  • Member since
    February, 2002
  • From: NE Ohio
  • 27 posts
Substituting LEDs for headlight bulbs
Posted by Dave553 on Monday, September 11, 2017 7:45 PM

I'd like to replace my Athearn RTR and Proto 2000 (DC, not DCC) headlight bulbs with LEDs.  Will LEDs connect to the board the same way as the bulbs do, and do I need resistors?

  • Member since
    December, 2015
  • 1,907 posts
Posted by BigDaddy on Monday, September 11, 2017 8:04 PM

Hmmm.  LED conversion is more often mentioned with DCC conversion

Why do you want to switch, longevity?

Decoder boards put out a constant voltage to the LED's.  Some have build in resistors and some don't.  No resistors and LED's are too bright, Plus some are only 3v.

In other threads Proto 2000 GP's were 3 volt and Athearn's were 1.5 volt.  My old train set locos headlights varied with throttle.  Are modern DC locos fixed output to the headlight?

I don't really have an answer for you, I'm posting to find out what I don't know. 




COB Potomac & Northern

By the Chesapeake Bay

  • Member since
    February, 2002
  • From: Reading, PA
  • 22,657 posts
Posted by rrinker on Tuesday, September 12, 2017 6:20 AM

 Neither is likely to provide enough voltage to light white LEDs because of the way they are wired. LEDs aren;t exactly practical for DC, becuase they won;t come on below a certain voltage, and the resistor value that lights them up nicely at slow speeds results in too much current at full speed.

 There are options, there was just another thread about this the other day. A constant current device can be used to feed the LED which menas that from the time it comes on all the way to full throttle it gets the same current (and stays the same brightness as a result). The downside if that the constant current device also uses some voltage, so now the minimum speed at which the LED lights up is even higher.



Modeling the Reading Railroad in the 1950's


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  • Member since
    October, 2005
  • From: Detroit, Michigan
  • 2,200 posts
Posted by Soo Line fan on Friday, September 15, 2017 1:17 PM

I use 470 ohm resistors with leds on all of my dc engines. None have burned out but I seldom run wot for very long. It's a big improvement over the crappy incandescent lighting. A brass light tube will keep from illuminating the cab. It's not perfect but before I install a constant lighting circuit, I would convert to dcc.


  • Member since
    November, 2003
  • 210 posts
Posted by Ron High on Saturday, September 16, 2017 11:49 AM

I run DC and I use LEDs with a 1000 ohm resistor. They come on early enough and they look good . In a few newer engines with DCC boards I have removed the DCC board and wired the LED and resistors direct to the pickup. removal of the DCC or light boards allows more room for added weight.

In the diesels with the smaller dual sealed beam type headlights I have used short lenghts of fiber optics fed through the headlight housing and into to the body with a small length of tubing. Place the LED in the end of the tubing. you can mount this inside the body shell any where there is more room.

Ron High

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