DCC mixed with DC

Discussion in 'DCC Control' started by steve, Apr 11, 2019.

  1. steve

    steve Full Member

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    I need some help.

    I am in the process of building a layout based on Tillig HO/HOe dual gauge track. The layout design is based on my version of Gary's lovely inglenook designs, Chris's "00 Inglenook and more" layout, and Toto's feedback about Ian's layout.

    I have a few HO DCC controlled locomotives, and a couple of Eureka rail motors that are really lovely.

    I have a Roco DC Hoe steam loco and propose to buy a Roco DCC HOe diesel loco.

    Because of the dual gauge track and the complication of DCC and DC mixed control operation, I know that I cannot run DCC and DC on the HOe section of the rack at the same time, but I would like to be able to run DC on the HOe and DCC on the HO section at the same time.

    Does anyone have experience in doing this or something similar.

    I think that the other alternative is to electrically block sections.

    Thanks
    Steve
     
  2. bobcom52

    bobcom52 Full Member

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    Consider this. If you intend to feed the narrow gauge with (say) dc and the standard gauge with DCC at the same time that means one rail will be common to both power sources. All will be OK until there is a short at a point or derailment leading to the dc rail being joined to the DCC rail. At that point both controllers may let smoke out.
    Cheers
    Bob
     
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  3. SRman

    SRman Full Member

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    That was my first thought too, Bob.

    My advice to Steve, for what it's worth, is to not mix DC and DCC, but run one or the other at any given time. For sure, it is possible to switch one pair f rails from DC to DCC using a common return, but any mishap on the tracks could end in tears.

    My own layout allows for switching between DC and DCC on the lower level only (plus the programming/test track). My upper level tracks remain permanently on DCC, but there is absolutely no connection between the upper and lower levels, and no chance that anything can bridge the tracks on both levels.
     
  4. Toto

    Toto Staff Member Founder Administrator

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    Solid advice I think.
     
  5. steve

    steve Full Member

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    I thank you all for your considered responses. I had not thought of derailments in terms of short circuiting and "smoke", followed by tears

    I think it was all a bit of a long shot. It is not going to be an issue for me to either to isolate the HOe sections completely and run these as DC, and if the Roco Steam loco is converted to DCC all will be good.

    Then I have the issue of wiring the three (3) rails on the dual gauge sections. Need to think that on through

    Thank you all very much. I will keep you posted, no smoke, no tears
     
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  6. Gary

    Gary Will the real Gary please stand up... Staff Member Administrator

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    Interesting thought you have with running both dc and dcc together. I do know that the 'Stoney Creek' layout at the AMRA Club Room in Mortdale (Sydney) run both dc and dcc together. A dc controlled train can be on the same track as a dc controlled train. I don't know how they have done this, but I do know the man behind the electronics side of the club's layout, but unfortunately he is no longer a member... I will probably run into him at one of the upcoming exhibitions next month.

    Cheers, Gary.
     
  7. steve

    steve Full Member

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    Thanks Gary

    In theory a DCC system (considered as AC in this case), can sit on a DC voltage level (or DC bias), or share a common rail (bus) with a DC rail (either + positive or - negative). The important thing is that they do not contact at two (2) points. In that case they can operate quite independently, sharing a common point.

    This is normal practice an many electronic circuits such as in direct coupled audio amplifiers etc. In the case of DCC shared with DC it is not quite the same, as model railways move and accidents do happen. They share a common rail, and the closeness of the other rail at crossings etc introduces a level of risk, such as with derailments.

    I am sort of moving away from my initial plan and keeping DC sections and DCC sections unless I can convert all locos to DCC.

    I still like the thought of experimenting with this concept, and would like to try and catch up with you at the Epping club show at Rosehill.

    Thanks and regards
    Steve
     
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  8. Andy_Sollis

    Andy_Sollis Full Member

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    A number of dcc decoders will support running on DC, such as powering the motor and the lights. Some (where fitted) will do the sound, but obviously they don’t have the extra functions in DC as you do with a DCC controller.

    My first thought would be to see which decoders are fitted in to what. Do they have a run on dcc option? ... secondly is it enabled? If yes, enable it. (Sometimes a dc section on DCC will simply make the loco brake and not control it as such.. check what specs you have- here is where a SPROG II and decoder Pro come in handy to check settings on a computer screen with tick boxes.)

    Then just run these along side the DC locos on a dc controller and sideline the None DC compatible locos/decoders until you can finance the DCC controller to make the full DCC switch. That way, less chance of motors or decoders letting the smoke out!

    Just a thought and doesn’t stop the fun in the mean time? :scratchchin:
     
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  9. steve

    steve Full Member

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    Thanks Andy

    Good points. I have not fitted any decoders myself. They have all come fitted within the model, but I should be able to interrogate the decoder to find out.

    I have an NCE Power Cab already, so I can do that.

    My one and only DC loco is a Roco HOe steam loco. I might take this back to the supplier and see if itcan be upgraded
     
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  10. steve

    steve Full Member

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    One step closer to full DCC. The local supplier of mainly European models had a 20% off sale for all purchases of shop stock over Ester. This included the little Roco HOe diesel with DCC and sound. This was too good to let slip, so my layout loo fleet is one step closer to being full DCC.

    Photo attached of the real thing and the model. Really nice View attachment 13148 View attachment 13149

    Regards
    Steve

    roco33293.jpg 243791 Steve.jpg
     
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