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Re-wiring a Locomotive

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  • Member since
    October 2006
  • From: Western, MA
  • 8,571 posts
Posted by richg1998 on Friday, March 1, 2019 2:28 PM

If you run a decoder on DC, you have to turn the power pack up higher than a straight DC loco. The logic on the decoder does not wake up until the DC is at about five volts. Maybe a couple volts more for the loco to move. Nature of the beast. Many have reported that.

Oh, if you see a good price for the Bachmann EZ Command DCC system, pass. It only allows programming the loco number. You cannot change CV's or reset a flaky decoder. I just saw a disappointed user in the Bachmann forums again.

Rich

If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.

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Posted by wjstix on Friday, March 1, 2019 1:54 PM

Athearn BB engine's chassis / motor set-up were created at least half century ago, so have been out of date for some time. I would say, since it sounds like eventually you will go to DCC, it probably would make more sense to just convert the engine to DCC, rather than take it apart to make the wiring for DC more reliable, only to take it apart again a year or so later to re-do it for DCC.

Most if not all DCC decoders are set up to allow DC to pass through them, unless you intentionally set them up to not allow it. So if you buy an engine that comes with a DCC decoder installed, you can still run it on DC. A good decoder isn't that pricey if you don't go for sound - $20 give or take - so I'd just do it all at once.

Numerous books on DCC, magazine articles, YouTube videos, websites have information on how to do the conversion. It may seem intimidating, but if you take it slowly step-by-step it's really not.

Stix
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Posted by richg1998 on Wednesday, February 27, 2019 8:44 PM

Shrink also comes in NMRA colors like the wire and get some Kapton tape from same places. Much better than electrical tape. Kapton is thin and strong. Not messy like electrical.

Rich

If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.

  • Member since
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  • From: Shenandoah Valley
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Posted by BigDaddy on Wednesday, February 27, 2019 7:37 PM

Hey Amanda

If DCC is in your future, you can buy a pack of DCC wire, of all the appropriate colors, in 30 ga, from one of the online DCC stores....Tony's train store, Litchfield Station Streamilined Backshop, or Yankee Dabler

You want the smallest heat shrink tube they sell.

Henry

COB Potomac & Northern

Shenandoah Valley

  • Member since
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Posted by richg1998 on Wednesday, February 27, 2019 7:13 PM

I have used Veroboard obtained from the UK via ebay, maybe eight to ten years ago. It proved handy for reducing the amount of wiring and wire splices in a few locos.No wire splices covered with shrink.

I used #30 wire in my HO locos. I do remember the #30 I used had more than seven strands and quite flexible and rubber covered, not plastic covered. Made a difference for wiring diesel trucks. The wires were not as stiff as a lot of #30. Wire from an old PC mouse is quite nice.

No need for any larger wire size.

For a couple LED's I used #44 enameled wire as it was easy to hide in a narrow area.

The Veroboard was handy for various electrons projects at the time.

Rich

If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.

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Posted by Monon Railroader on Wednesday, February 27, 2019 5:50 PM

Thanks for all the input everyone. I need to start rooting through my electrical stuff to see what I need to get started.

On a related note I just got a older Athearn SW7 and was told it just needed some TLC. Well, it arrived today and it does need TLC... Tons of Loving Care! :-)  Anyhow, it's all good, the little beastie has a good home. Got her apart and found the major hiccups and ready to rejigger the loco.

Thanks for the ideas!

Amanda

          

 

  • Member since
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  • From: SE. WI.
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Posted by mbinsewi on Monday, February 25, 2019 9:28 AM

Yes, you can get the harness for DCC, or you can get the decoder, as it comes with the harness, wire it in, and then install a jumper plug, or dummy plug, so you can run on DC, you will have a "DCC Ready" loco.  Unplug the dummy plug, plug in the decoder.

But if your going to do that, just leave it DCC and go.

The OP makes it sound like she (Amanda?) does not yet have a DCC system.  Just wants to make a better electrical path for her Athearn BB loco.

When she gets her DCC system, her new Athearn "DCC Ready" that she already has, will simply need the decoder plugged in where the dummy plug is.

Mike.

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Posted by doctorwayne on Monday, February 25, 2019 9:15 AM

It's the OP's intention to go with DCC, but her question is basically about replacing the original Athearn power distribution system with something more reliable.

The solutions showing wire in place of the metal "leaves" answers her question, I think, and for DCC, the wires would go to the decoder, rather than directly to the motor.

I have a locomotive to which I'll be adding DCC for a friend, and will be here with my own questions when I get to that job.

Wayne

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Posted by BigDaddy on Monday, February 25, 2019 9:05 AM

mbinsewi
There really is no way to do all of this is preperation for DCC. The motor wiring for DCC is different, so when you convert this loco, you'll be tearing all of the above procedure out, and starting over.

Maybe not.  We had a thread about un-DCC'ing a loco. 

http://cs.trains.com/mrr/f/744/t/274494.aspx

If there is room, you could create your own DCC ready plug.

However, if it was me, I'd bite the bullet and go DCC and control your locos and not your track.

Henry

COB Potomac & Northern

Shenandoah Valley

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Posted by RR_Mel on Monday, February 25, 2019 8:43 AM

This is a before DCC conversion rewire of an Athearn SD40-2 frame about 15 years ago.  Back in the day I rewired all of my BB Athearn diesels like the one below.
 
 
After removing the snap off power “metal leaves” I soldered #24 stranded hookup wire to the two motor endbell/brush retainers, red to the trucks and black to the frame (light bracket).  I cut the “metal leaves” off the trucks about a quarter inch above the truck frames and soldered directly to them.  Leave enough wire so that it can flex without breaking at the solder joint.
 
 
 
Mel
 
 
My Model Railroad   
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.
 
  • Member since
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Posted by mbinsewi on Monday, February 25, 2019 6:47 AM

To get rid of the "leaves", the strip across the top of the loco, remove it. Then solder a piece of fine stranded wire, like maybe 24g.  to the top of the front and rear metal "L" shaped piece that sticks up on each truck, to the top brass strip on the motor.

Here's a great "how-to" for Athearn BB locos:

http://www.mcor-nmra.org/Publications/Articles/Athearn_TuneUp.php

There really is no way to do all of this is preperation for DCC.  The motor wiring for DCC is different, so when you convert this loco, you'll be tearing all of the above procedure out, and starting over.

The Athearn BB loco "minus" side of the electrical equation runs throught the trucks, the frame, and to the bottom of the motor.

When you convert to DCC all of this changes.  The motor will need to be isolated from the frame.

It's an easy "hard wire" so don't be concerned.  

Have fun!

Mike.

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Posted by doctorwayne on Sunday, February 24, 2019 11:59 PM

My "wisdom" doesn't include much in the way of DCC, but here are a couple of photos illustrating how to get power to the motor after removing most of the metal leaves.

This is an Athearn Blue Box SW7 (originally erroneously marketed as an SW1500, I think)...

The black wires are soldered on to the shortened cut-off vertical "leaves" on each truck and both of the red wires are soldered to the plate atop the trucks (normally hidden by the driveshafts).

I ran the wires to a small piece of copper-clad circuit board, as seen in the first photo, with the two sides isolated from one another.  I then soldered rail joiners to the copper, and added short lengths of rail to the ends of the wires, including those to the motor.  This was to allow easy removal of the trucks or motor, with no need to unsolder anything. 

For your DCC decoder, the attachment would be the pairs of like-coloured wires from the trucks to the proper decoder leads, and the appropriate wires from the decoder to the motor.

Sorry I can't provide more info on decoder installation, but I'm strictly a DC operator.

Wayne

  • Member since
    July 2018
  • 43 posts
Re-wiring a Locomotive
Posted by Monon Railroader on Sunday, February 24, 2019 11:21 PM

Hey guys!

I recently bought an Atheran (Blue Box) GP60 and I like the beastie. I took the shell off to prepare it to be painted to my Monon colors. Then I noticed that power in the loco is being distributed by metal "leaves" sliding over one another! Ack! That just grates against my nerd being!

I'm thinking about going with DCC for my miniscule rail empire. Is there a, sort of, simple way to re-route all this electrical distribution with wires that would make DCC more doable? Not so simple would work too, I'd just like simpler... better! :-)

My decision to lean toward DCC was the purchase of an Athearn RTR P42DC which is DCC ready. Making the GP60 DCC capable might make the prospect of adapting my Kato NW2!

Just casting out for tips, tricks, links or even someone saying "You're not completely carzy here!".

Thanks for y'alls wisdom!

Amanda Ward!

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