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Old wiring standard?

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Old wiring standard?
Posted by RR_Mel on Tuesday, January 14, 2020 6:33 PM

Before NMRA Specs was there a manufactures standard on which rail was the tender? Maybe a handshake agreement or such?
 
I have a lot of old clunkers (AHM Mantua Varney) and some are tender left rail power pickup and some are right rail power pickup.
 
My first HO locomotive (1951) was a MDC Roundhouse 0-6-0 Kit and the instructions said to put the insolated wheels on the left side (Fireman side) so the metal frame was “hot” on the right rail (Engineer side) making the tender “hot” on the left rail.  Was that a manufacture standard or just MDC.
 
 
Mel
 
 
 
My Model Railroad   
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.
 
  • Member since
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  • From: Reading, PA
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Posted by rrinker on Tuesday, January 14, 2020 7:02 PM

 For DC operation, the NMRA standard was right hand rail positive was forward. I'd guess most often it was the lower motor brush that was grounded to the loco frame, with the wire coming off the top one, but there was nothing that said it had to be that way. 

                                    --Randy


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

  • Member since
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Posted by RR_Mel on Tuesday, January 14, 2020 9:10 PM

Before NMRA Specs was there a manufactures standard on which rail was the tender?
 
I have a lot of old clunkers and some are tender left rail power pickup and some are right rail power pickup.
 
I’m kind of wondering about the frame connection.  All the old Athearn frames are connected to the right rail positive forward but early Mantua and some of the AHM locomotives have the frame connected to the left rail.  The direction is always right rail positive forward on everything.
 
My concern came up when I was rewiring a newer Rivarossi Cab Forward for DCC.  It’s a mid 90s version with locomotive full power pickup, no tender power pickup needed.  The front drivers are Right rail pickup and the rear drivers are left rail frame pickup.  The earlier Rivarossi Cab Forwards had the frame connected to the right rail.
 
This particular Cab Forward is the only one I bought new and it’s different.  I originally remotored and converted it to DCC in 2006 but never got that deep in the wiring until today, sorta confused me.  I spent the last several hours going over all of my locomotives checking them to make sure they are all wired correctly, so far so good.
 
 
 
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 BigDaddy on Tuesday, January 14, 2020 9:26 PM

RR_Mel
Before NMRA Specs was there a manufactures standard on which rail was the tender?

RR_Mel
All the old Athearn frames are connected to the right rail positive forward but early Mantua and some of the AHM locomotives have the frame connected to the left rail.

If the frames are connected differently, then the motors must be connected differently.  The goal is to have have all the locos move in he same direction, back when there were only DC controllers.  How that would have been phrased is a touch beyond my paygrade.

Henry

COB Potomac & Northern

By the Chesapeake Bay

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  • From: Reading, PA
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Posted by rrinker on Wednesday, January 15, 2020 7:26 AM

 I think you answered the question yourself when you said some tenders are left rail pickup and som are right rail pickup. Prior to the NMRA< there really was no standardization of anything. You'd think that a given manufacturer would amke all their locos the same, but it was also a time of rapid advances and what worked well on one model, when they came out with a new one a year or two later, they may have found something else worked better.

 I'm not sure it even matters. DCC doesn't care. The track pickups can be hooked up any old way, it's the motor drive leads that matter to make sure the loco moved forward when forward is selected on the throttle. It matters in DC only so far as that when the right rail is positive, it's connected to whichever motor terminal makes the motor spin in a way that the loco moves forward. There hav ebeen locos sold even AFTER the NMRA came along that were wired backwards.

 And nothing says the opposite rail can't be the frame ground in a BB loco - just swap the front and rear trucks around, now the left rail is the fram instead of the right rail. And it will run the opposite way, unless you flip the motor over. It's a way to fix the shorting through the couplers, but a rather extreme one - if you use metal couplers in the metal pockets on a BB loco, and you flip one around so they run back to back, they will already both move in the right direction, but on one loco, the frame is the left rail, and the other, the frame is the right rail, so you get a short through the coupler. The more sensibe fix it to either use one of the plastic chank couplers, or grind the mounting area flat and use the Kadee box (plastic) to mount the coupler in. 

                                         --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

  • Member since
    January 2009
  • 4,642 posts
Posted by RR_Mel on Wednesday, January 15, 2020 8:57 AM

Randy
 
I know that the frame doesn’t make any difference but I strive to keep all my mods (in this case my DCC wiring) as close to the same as possible.
 
As most of you know I’m infatuated with the older Rivarossi articulateds and discovering the difference in this one really shook me up.  So much so that I checked all of my DCC conversion for their wiring.
 
As I only have a few decoders I wired every one of my locomotives (over 70) for DCC operation and use a DCC Dummy plug for DC operation.  My layout is DC or DCC and I run more in DC mode than DCC.
 
Because I have so many Cab Forwards I have two oil tenders with dual speakers and DCC sound decoders that are not numbered so that I can use them behind any of my 15 Cab Forwards.  I kitbashed four AC-10s into AC-9s, 2-8-8-4 Yellowstones that use the same oil tenders for DCC operqation.  The non DCC locomotives have the DCC Dummy plug installed and I run them in DC mode.
 
I also have a couple of AC-3s kitbashed from Y6Bs with the old style scratch built oil tenders as well as two Y6B kitbashed into SP MC-1s.  I kept one Y6B as original.
 
I have always used insolated couplers on all of my locomotives because of the shorting possibility but even so I made every Athearn diesel the same with right rail positive forward.  I guess a bit of OCD in me, I try to keep everything the same or as close as possible.
 
Thanks guys for your input, great as always.
 
 
 
Mel
 
 
 
My Model Railroad   
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.
 

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