Re: decoder installation in a IHC GG1

Mark Gurries

On Jan 5, 2015, at 10:19 PM, 'Glenn' ghazel@... [WiringForDCC] <WiringForDCC@...> wrote:

IMHO: Run as two rail only and forget getting power from the overhead.

Yes that is always the option but does not address the problem.  Nothing is improved or solved.

If you are running engines only from the overhead, then wire that as one side of the polarity and both rails as the other. Traction modelers do this in both DC and DCC

Understood as I stated before.   But I know that not everyone does this. 

Yes there is a solution and a benefit, also more problems. You would need to select which rail would be the same polarity as the overhead

Right as I stated.

and duplicate all electrical nuances, I.e. gaps, polarity reversal, insulated frogs, etc. 

True but not nearly as bad.   Pantograph polarity issue would be limited to

1) Reverse loops.
2) Crossings.
3) Wye's

In such cases, the pantograph section where the opposing polarities would meet would be replaced by a short dead section (few inches) of pantograph power and depend 100% on the all wheel pickup until you passed clear of the pantograph polarity zone.  Think of it as a very large gap.  This solution is very simple to implement.  No small precision gaps required.

The pantograph within the reversing section would remain assigned to the same rail as before and have its polarity determined by the autoreverser.

There would not be any polarity issue for turnouts.
It would also mean more wiring.

Wiring yes.  But not much more wiring since you simply taping into the existing close by track feeders for the rail assigned to be the pantograph power.

From: WiringForDCC@... [mailto:WiringForDCC@...]
Sent: Monday, January 05, 2015 19:27
To: $WiringForDCC
Subject: Re: [WiringForDCC] decoder installation in a IHC GG1


I am not an "electric engine" expert as it relates to model using live overhead wire power pickup.   Here are my thoughts on the subject.


IF the engine was design to ONLY pickup power from the pantograph, then a “switch" to select between rail and pantograph is not required.




IF the engine offers the option of using all wheel pick up or pantograph pickup, then we have options for simultaneous dual power pickup.    The only question is what polarity does the pantograph represent relative to the wheel pickup.  I do not know if there is a “NMRA standard” governing this and even if there is how many follow it.  In this case, a switch is only needed to set the polarity of the pantograph power with respect to the wheel pickup power.  In one direction it would represent a short and in the other it would offer supplemental power pickup.  One can quickly figure out which position it needs to be in.  The dual power pickup, both rails + pantograph, physically gives you the same effect as having more wheel pickup.  Granted it only improves pickup for one rail, but it does cut the problem in half giving one more reliable power pickup operation.


Adding dual power pickup would be far cheaper than adding a Keep Alive.   But I agree if the dual pickup power option does not solve your power pickup problem, then keep alive is your next best bet.



On Jan 5, 2015, at 7:20 AM, 'Vollrath, Don' dvollrath@... [WiringForDCC] <WiringForDCC@...> wrote:

The DCC decoder should work from the pantograph or rail/wheel pick-up. Using a SPDT switch to select either one or the other modes makes sense. [Obviously the wheels must be isolated for two rail pick-up to avoid shorting out any DCC signal that is on the rails, motor isolated from frame, etc.]

However pantograph pick-up for DCC may suffer from many intermittent breaks in the connection. If this happens, try adding one of the ‘keep-alive’ / carry-over gadgets to improve continuity pf power.



From: WiringForDCC@... [mailto:WiringForDCC@...]
Sent: Monday, January 05, 2015 7:19 AM
To: wiringfordcc@...
Subject: [WiringForDCC] decoder installation in a IHC GG1


I've recently installed a decoder in a IHC GG1 (two motors), It works fine. But I have a doubt. In DC, operation can be done through the pantographs or both rails by means of a switch in the bottom of the chassis. To install the decoder I had to disconnect the wire linked to the pantographs. I’ve soldered the black wire of the decoder to the terminal in the middle of the switch, which is linked to the left wheels pick-up in the right position of the switch button. In the other position, the black wire would be linked to the pantographs, if I've soldered the respective wire to the left terminal of the switch. Can I resolder it to the switch for operation through the pantographs in DCC? Or is it not advisable?







Best Regards,


Mark Gurries

Electrical Engineer

DCC Website & NMRA DCC Clinics:




Best Regards,

Mark Gurries
Electrical Engineer
DCC Website & NMRA DCC Clinics:

Join to automatically receive all group messages.