Block Wiring DCC?

Discussion in 'DCC & Electronics' started by green_elite_cab, Jan 30, 2006.

  1. green_elite_cab

    green_elite_cab Keep It Moving!

    I'm getting a DCC System ( my Prodgy Express is in the mail) but I have some locomotives that Are going to be difficult to convert over to DCC, like my GE 44 ton switcher. Its an important part of operations.

    Now my question is, can i run this one locomotive off dcc? I have my layout block wired already. Couldn't I technicaly hook up the DCC to Cab A on my selector, and have a regular DC power pack control my 44 tonner?
  2. baldwinjl

    baldwinjl Member

    The big risk you run is that you absolutely cannot let the DC and DCC portions get shorted together. I'd say this means that you would want to ensure that there was a dead block on either side of any DC block. So there would be some more switches required to pull that off. Other than that it could be done, I think. But, you can probably convert the loco, though it might be difficult. Some one else could well know how to do it.

  3. green_elite_cab

    green_elite_cab Keep It Moving!

    the problem is that the GE 44 tonner has a complicated process for DCC as i have an older spectrum one. It supposedly requires lots of cutting and fiddling. I think there is a thread i made about this somewhere on here
  4. baldwinjl

    baldwinjl Member

    Cutting and fiddling can and probably will certainly be a pain, but the alternative is really not attractive. Unless you ensure (and I mean by that the switches are interlocked, not that you do it as a matter of procedure) that the blocks can't short, sooner or later you are going to cross from a DC block to a DCC block, and I don't think the DCC system is going to be happy. You've only got to install the decoder once, you'd get the inconvienince of operating without it every day.

  5. green_elite_cab

    green_elite_cab Keep It Moving!

    I finaly gained acess to the source of the wires, but i'm not sure even a small decoder will fit. Atleast it only seems like cutting and soldering wires.
  6. MasonJar

    MasonJar It's not rocket surgery

    Does the Prodigy system give you the option of running one loco without a decoder? It is not a great work-around, but the Digitrax systems do offer this.

    As for powering parts of the layout with DCC and parts with DC, I would say it does not sound like a very good idea for he reasons Jeff listed... :(

    Have you considered an Nscale (or even Zscale) decoder for the 44 tonner? If they can handle the amps, then it should be fine. You can also get someone to put the decoder in the engine for you.

  7. green_elite_cab

    green_elite_cab Keep It Moving!

    yeah, i'm gonna buy a pair of DZ143 s from Digitrax i think. one for the 44 tonner, and another for my Atlas ALP44
  8. davidstrains

    davidstrains Active Member

    Most systems allow for loco address "00" to run as a non-dcc engine on the dcc layout using the dcc controller. You should check your documentation to see if this works on your system. I do this with several older n-scale locos that I cannot modify and I do not want to have someone else modify the frames to get them to work. I just use them one at a time and then store them on an electrically dead track. This would be a much easier solution than messing up a good loco that might be too difficult to modify for dcc. It also eliminates the dual dc-dcc problem.

    Just a thought.
  9. Woodie

    Woodie Active Member

    If I recall correctly, and I'm pretty vague on this, but I read in my DCC command station and decoder info that there is a specific function (to do with signalling) that allows you to have sections of DC track. There is a CV for "DC detect" (or something like that) that is used for some purpose or other. (I said I was vauge about it) And I'm not referring to the CV that is a yes/no to allow a DCC loco to be controlled by a DC controller (i.e. bypass the decocder when DC voltage is detected).

    It is not a problem to allow a DCC loco to run on DC track. I'd be more concerned about a non-decoderised loco crossing (accidentally) on to DCC track, with > 14 Volts AC power across it.

    I'll check what the documentaitons says about this DC detect bizzo, and what it's for, tonight when I get home.
  10. baldwinjl

    baldwinjl Member

    I think you are thinking of the CV to allow the decoder to sense DC or DCC, and use what's there. The problem is that if you go from one section to the other the loco will be shorting the two control systems together, and the results will most likely not be pretty.

    Many DC locos will run acceptably on "channel 0", but some won't. There is also an annoying hum, and some motors dislike it enough to fail.

  11. davidstrains

    davidstrains Active Member


    I agree, however, the dual dc-dcc concept working at the same time is just an accident waiting to happen. I don't think that the concept is meant to be operated simultaneously.

    In the instance in this thread, it sounds like he wants to run a DCC loco and a DC loco at the same time. The potential for a dcc-dc short just seems too great. It would be better to operate in a straight DC mode or DCC mode during the session, but not both at the same time. Or use the "00" address in the DCC system and add another DCC controller to the Prodigy (if it will accept a second controller)

    I think what "green" is trying to do might be doable with the Digitrax Zephyr using the dc power pack in the "jump throttle" mode. But I think that the locos have to be DCC configured. I have not read the Zephyr documentation so that is not an absolute "known" opinion. I am not familiar with the Prodigy so I don't know how it treats the concept.
  12. MasonJar

    MasonJar It's not rocket surgery

    When the DC powerpack is operating as a "jump throttle", it is for all intents and purposes a DCC throttle. The entire layout is being powered by DCC. Whether the jump throttle is addressing a decoderized loco or not is irrelevant (bearing in mind that non-decoderized locos can only operate on address "00").

    I guess it is in the interpretation of

    Does this mean he wants to run some blocks with DCC, and others (where the 44-tonner will run) using DC power?

    This would seem to indicate that he has traditional block control, but wants to replace Cab A with a DCC unit, while retaining the DC powerpack for Cab B.

    If this is indeed the case, I would say it is not a good idea (unless Woodie has found some sort of "workaround").

  13. davidstrains

    davidstrains Active Member


    Well said. I think you said it better than I did. and I agree - not a good idea.
  14. green_elite_cab

    green_elite_cab Keep It Moving!

    Well, My 44 tonner doesn't move through out the layout, it stays in the industrial area, where it is pretty much the only locomotive that can switch in that space. Here, the red tracks are the tracks that would need to handle both DCC and DC locomtives. the blue tracks would only be used by the 44 tonner. The green track is a possible dead track that i can swith on and off.

    My industrial area is already divided into 2 blocks, one main block that seperates the industrial area from the rest of the layout, and one additional block where the 44 tonner is parked, so that shorter trains can back their frieght cars up the industrial lead. Since the only time a DCC equipped locomotive needs to be in there is when picking up and placeing cars on the red and green tracks, I figure that once its done and the DCC locomotive safely off the industrial tracks, i could switch it back over to DC.

    In my mind, it works exactly the same as my DC block wired layout now, except i'm useing to different forms of power.

    Athough, more research as shown that i might be able to more easily install DCC in the 44 tonner, so i might not have to do any of this.

    Attached Files:

  15. green_elite_cab

    green_elite_cab Keep It Moving!

    thats basicly the plan.
  16. MasonJar

    MasonJar It's not rocket surgery

    That diagram suddenly brought to mind a layout I know of where the owner does what you are intending... he runs the switcher with DC power, but the rest of the layout with DCC. However, I believe that the two areas are not "switchable" - i.e. each is dedicated.

    I will investigate and get back to you...

  17. davidstrains

    davidstrains Active Member

    Wouldn't it be possible to use a dpst center off switch to isolate the power on that industrial section at the point where it comes off the main. That way the only power to an engine in that block is either DC or DCC and never both? - unless the engine strays back out to the main :oops:
  18. baldwinjl

    baldwinjl Member

    The theory is fine, but you need to have a length of dead track between the two sections so that you can't bridge the gap with a loco or any car with power pick-up. Be very careful....

  19. green_elite_cab

    green_elite_cab Keep It Moving!

    which would never happen unless i really stopped paying attention. most likely i'd reset the switch going from the main to the industrial park so that i'll be able to back in the rolling stock onto the track there. Since its behind a building, i'll have to keep an eye on things anyway. that is the most dangerous part. chances are i'll notice thoug that the freight cars are on the wrong track, and stop it before the 44 tonner hits the bad rail, considering how slow i creep it. I also run my freight clockwise, so a train will never go into the industrial park.
  20. green_elite_cab

    green_elite_cab Keep It Moving!

    that can be done. However I think i found a solution to my 44 tonner problems. i just need to rais up my allownce for a decoder. apperently i just need to solder the wires to their appropriate solder pads. I hadn't noticed these before. I was also told that the DCC ready 44 tonners had plugs in them, and apperently thats false. I'm pretty good at soldering, so i think i can manage. Its good to know i have options though.

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