DC/DCC dual operating engines

[Ralph S]

There was one post (Bachmann DCC on DC « on: April 02, 2010, 01:33:03 PM ») regarding the Bachmann controls but what I researched was the engines with OEM decoders that are dual mode and will run on both DC and DCC.

Question is: Is there such a thing as an engine that can operate on DC and/or DCC without all the separation or engine humm, and overheating issues.  Is Bachmann going to build these type engines in their line of products?  Or are the other engine manufacturers to do that? Or is this somebody's fantasy/dream of a new engine?

Also it would be of some help if someone could explain this dual mode decoder since I may be confused about this dual mode operation of an engine. 

If this is possible, the old DC power and new DCC power would get a hefty boost from consumers.

[jward]

The answer to your question is yes. Locomotives that can operate on DC or DCC without overheating do exist, and they are common.

To expand on that statement is to understand what a dual mode decoder is. Most decoders currently marketed are dual mode, that is, they are capable of running on both DCC or DC. This is a setting in the decoder programmong of CV29 which can be set by the user. But the factory default is to have analog conversion enabled so the locomotive can run on DC if necessary.

There are trade offs, however. A DCC locomotive running on DC will need 5 or 6 volts before it starts to move, due to the circuitry of the decoder. That's half the control arc of a typical DC power pack which puts out 12 volts. As a result, performance on DC may be sluggish, with a lower top speed than if it didn't have a decoder.

Some of prefer to disable the analog conversion. A DCC locomotive can be tricked into thinking it is running on DC, where voltage on the rails controls the speed. As DCC puts full voltage on the rails at all times, this will cause the locomotive to take off at full speed and the only way to regain control is to turn the track power off. Disabling the analog conversion prevents this from happening, but in the process you lose the ability to run on DC. I mention this because if, like me, you buy secondhand locomotives you may find the previous owner turned this feature off. A factory default reset, or reprogramming of CV29 will restore the ability to run on DC.

Another option you have is to wire both your DCC and DC controllers to a DPDT switch that would allow you to run either system at will. The whole layout should be set up as an either/or in this case. Either you're running DC or you're running DCC. Do not attempt a system where both systems are controlling tracks that connect to each other, even if they are electrically isolated from each other. Accidentally bridging the gaps between the two systems will cause severe damage to your controllers and possibly your locomotive.

[Hunt]

Caveat --- Not just any DC power pack can be used.

A locomotive with a dual mode decoder (i.e. can use DCC or DC power) only  operates well in analog mode using an electronically regulated  power pack to  supply filtered DC power. An older rheostat-style or pulse power pack will result in erratic operation thus must not be used. If the DC power pack has a pulse power switch, it must be turned off.

[Ralph S]

Fantastic information, but I still need a little bit more clarification.   So, let me state what I understand, thus far.   There are locomotives that are common and can operate on both DC or DCC.   So does that mean that I can buy a dual mode engine that will operate on DCC without doing some sort of software/hardware change and then operate it on DC on the same track? 
Yes, I understand the two (i.e., DC and DCC) cannot be energized on the same track at the same time.  Yes, I understand that train wheels crossing the gap will short both DC and DCC if crossed/connected.

But what I am wondering is, if this is a dual mode engine, then can this engine being on DCC power and you de-energize DCC track and re-energize the track with DC, will this same engine operate on DC track without any manual switch change or software change? 

Understand this is game changer for me if my understanding is correct, since I'm currently in the market to purchase new DCC engines.

[jward]

Yes, new engines with dual mode decoders will run on DCC or DC right out of the box. Just be aware that feature may be disabled on secondhand locomotives by the previous owner.

[Ralph S]

Do I have to ask for Dual mode on the DCC engine or is it standard on any of the manufacturer's  models?

I feel like I'm buying a car but need to make sure the dealer has these installed options on the car I'd purchase.

[jward]

Dual Mode decoders are standard in DCC equipped locomotives by Bachmann and Atlas. Not sure about others. Keep in mind that DCC ready means the locomotive does NOT have a decoder. DCC equipped means they do. Best thing to do is look for the description of the locomotive you want to buy. The manufacturers website should tell you if it has a dual mode decoder or not. While dual mode is an optional feature in decoders, most have it.