Re: Dual Mode? DCC/DC

Mark Gurries

This topic seems to have derailed into a layout question as opposed to YOUR decoder question.

Almost ALL decoders made past and present support both DC and DCC mode of operation.

The question is not if the decoder will support DC mode but how well it supports DC mode.   You can see a wide variation in the locomotives response to a DC throttle position.  Simply put is will not have as wide of a speed control range than the locomotive had BEFORE you installed the decoder.  Many considered this speed control in DC mode unacceptable.

Some History:  Some time ago, Atlas decided to market a new type of decoder with a marketing name of "Dual Mode”. By Dual ModeTM, they meant the decoder has a physical jumper plug that allows the modeler to select between DC-only operation or DCC and DC operation. With the plug in the DC-only position, a decoder equipped locomotive runs on a standard DC powered (analog) layout with no speed differential when compared to a similar non-decoder-equipped locomotive.  The locomotive shell had a roof top hatch that you removed exposed the jumper so you can change it on the fly.  You then put back the hatch.

These decoders are no long made but it has lead to some confusion in the market place to imply you must buy a specific decoder to run in both DC and DCC mode when that is not true at all.

Finally there is one downside to keeping the DC mode enabled (by default it is typically enabled) when running on DCC.   If there is a momentary short on the track, it can confuse the decoder and it will exit DCC mode and go to DC mode on the fly.   Unfortunately this results in a runaway locomotive under DCC mode where the only way to stop it is to kill layout power or grab the engine.

On Feb 20, 2020, at 5:04 PM, Duff & Polly M via Groups.Io <dpmeans@...> wrote:

I am sorry if this has been asked before, or if this question should go elsewhere.
I currently operate DC, mainly because of the number of locomotives that will need work.  I do have a few locomotives that are DCC Ready.
A club I am joining is DCC.  I am thinking I would like to equip one or two of my DCC Ready locomotives with decoders, so they can run at the club.  However, I would also like to use them also at home on my DC layout.

I have heard something about dual mode decoders that can automatically determine whether DC or DCC is available.  If these do what I think they do, are available, and not too too expensive, I am inclined towards this solution.

Are there negatives to this approach, and.or recommended methods?

Thank you.

Best Regards,

Mark Gurries
Electrical Engineer
DCC Website & NMRA DCC Clinics:

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