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Ted S posted:
Aegis21 posted:

I hope I can upload this short video of my test track home made (with tons of help from others before me) DCC++ system using JMRI decoder pro and arduino code and a controller shield I did develop myself.

Wow, amazing!!  That's great performance from what's basically a low end 60-year old toy!  Does the shield function to isolate the decoder from RFI?  I always thought DCC with Lionel-style universal motors wasn't possible.  Something about isolating the field winding from chassis ground?  Anyhow once the commercial systems came out, like so many others I traded in my curiosity for my credit card number.  Good on you for doing this and sharing it on the Forum!

It works so far on two tracks really well out of the gate. No shield was used, the decoder is clipped onto a frame piece of the body. The windings and brushes need to be isolated from ground which on all I have seen is the wire that grounds the motor to frame needs to be disconnected. Then the motor runs on the DC from the decoder.

So it is possible to run DCC on three rail systems. Now I have no idea how things will work outside of the lab in the "real world" of large layouts, dirty track, spikes from motor brushes etc. There has to be some good reason Lionel or MTH did not go the DCC route. All the smaller scales seem smitten with DCC so I am befuddled to say the least. Again, I have been out of the hobby for sometime, although I have kept pace with electronics over the years.



I have to correct some misinformation about DCC here.  DCC can be run on 3R just fine.  I do it, and so do others on the forum.  They can be found in the DCC section.  I have a couple brand new MTH PS-3 locomotives, I just flipped the switch to DCC, put them on my 3R layout and away I went.

As for running a combination of DCC/Legacy/TMCC/DCS this is what I know. 1) MTH has flat out said DCC and DCS are not compatible.  Their manual states if the locomotive see the command signal it isn't switched to that it will ignore it.  It will not hurt the locomotive to be set to the wrong thing, it just won't do anything. 2) DCC/TMCC - I have tried running the two together.  From my limited selection the TMCC locomotives either sat and did nothing and completely ignored the commands issued them, or they took off at full speed when addressed.  These were older TMCC locomotives, I can not say if the newer ERR boards would respond the same way. 3) DCC/Legacy - they are compatible, with some caveats.  First of all, Lionel sells Legacy/DCC locomotives, just not in O, until they release the hybrid 4-4-0s.  The locomotives they do sell are S gauge, and they listen for the command signal and reply to the one that is on the track.  I do not know what they do if both are on the track as that is not my gauge, nor know anyone personally in that gauge.  In O I have connected DCC and Legacy to the same track and had both powered up.  You can find my thread on the matter in the DCC section.  I found that all Legacy featured worked, except for electrocouplers.  Those would do one of three things and it was different for different Legacy locomotives; A) nothing at all, B) fire just fine, or C) nothing when you pushed the button, but as soon as power was cut to the track they fired.  Result C is the worst case as it means that your coupler was energized the whole time and could burn out if power was not cut in a timely manner.  This leads me to believe that with a slight design change that Legacy locomotives could run on a combined DCC/Legacy layout just fine.  And as of right now I do so, I just make sure I don't use the electrocouplers.  DCC locomotives don't care that there is a TMCC/Legacy signal on the track at all and function just fine.

As for converting old AC locomotives to DCC, I have heard that some people have done it, but I do not know the details.  I do have a couple myself I would love to do so with, but will most likely just convert them to TMCC with ERR boards.  90% of my old MTH Protosound 1 locomotives will get converted to DCC.  I know that is long, but I wanted to get out there my personal experience on the matter.  You can run all the systems on the same layout if setup correctly.  When complete my layout will have conventional, TMCC/Legacy, and DCC.  I will have switches to change between them so that I don't have to worry about my TMCC or conventional locomotives taking off.  Good luck.


Thank you for all of this information and your real life experiences with these systems. Since I do not have large dollars invested in a control system as of yet, I have the luxury of trying things out slowly. Please correct me if my interpretation of your write up is off in anyway.  My personal take away from this is to set up DCC on a track with a converted old conventional engine that I have modified to DCC operation. Once that is fully functional and if there aren't insurmountable hurdles, purchase a Lionel Legacy control and put both on the track and check out how they operate or not. Of course paying attention to electrocoiuplers. My thinking would be as follows: if this works I can run the MTH loco's switched to DCC (not sure how many have both capabilities DCC & DCS) And all Lionel Legacy loco's and my old converted conventional loco's.

If this fails then my route would be to use ERR conversions on old conventional loco's, Hook up the Legacy system and purchase a DCS system. Before your input I was tending to go the Legacy/DCS route (which I think was over 1k in costs) So I would wind up there in the long run. Does this sound somewhat logical or totally nuts!



Any factory O-scale stuff you buy from Lionel will not be DCC compatible, that's something to consider.  I think you'll come to grief if you try to run DCC and either DCS or TMCC/Legacy at the same time on the same track, they will fight and lose.

I don't do DCC, so it made my life easy.  I can run DCS, TMCC/Legacy, and any of the LionChief flavors at the same time on the same tracks.


Yes the DCC signal is essentially a square wave that has different pulse width's for encoding infomation onto the track. In my case the DC supply I use is set at 14VDC and then the driver boards chop it up with encoded data. 

I certainly "see" where the DCS signal is not compatible. Just not sure if Legacy is or isn't.  Maybe I'll find out. One catch with my "plan" I do not have a legacy loco! LOL

And again, the option of DCS & Legacy maybe my ultimate route.

I know one thing from years in electronics, NEVER let the blue smoke out of the components! You never can put it back in and have working results.

Last edited by Aegis21

I can assure you from my brief tests, that TMCC/Legacy does NOT like running on a track with the DCC signal!  Many of the TMCC driver boards depend on AC on the tracks, and they really objected to the DCC signal to the point they didn't run at all.  At least I didn't cook anything.  TMCC and Legacy manuals are pretty explicit about the power source, that being AC.  Until the advent of the RCMC for Legacy around 2010-2011, the early Legacy used triacs in lighting and smoke circuits, those would not function with DCC waveforms.  I don't know about modern Legacy, and I have no intention of risking one of mine in the experiment.  Since a huge number of my locomotives that run TMCC, early Legacy, or PS/2 don't work with DCC voltages, DCC simply isn't in my future.

Last edited by gunrunnerjohn

I have run Lionel Legacy locomotives with Legacy base connected to a DCC powered track, with my ZW-C powering NCE 10 amp booster set to 18V at the rail.  I have run 2 MTH PS-3 equipped locomotives set to DCC, a Lionel conventional locomotive (with DC motor) converted to ESU LokSound L DCC decoder with the Lionel Legacy equipped Heavy Mikado, NYC S-2 electric, and B6sb.  I don't remember if I ran the Lionel Legacy 10 wheeler or not, but it's most likely I did.  I had no issues controlling the Legacy locomotives, except for the electrocoupler.  All other Legacy functions work as expected.  All those locomotives have continued to run fine after my testing.  Like I said my TMCC locomotives did not like the DCC signal, they either ignored commands, or shot off at full speed when issued a command.  They have also continued to work just fine once the DCC signal was removed.  Based on my personal results I do not have any fears at having Legacy locomotive on the track with a DCC signal.  With that said, I don't plan on running them together often.  As I'll have block powered sidings, Legacy/TMCC and DCC locomotives will be parked on separate sidings that will be unpowered when the other command system is in control of the rail.  My block controllers and turnout controllers will all be LCS controlled, the presence of DCC hasn't caused them any issues.  In fact the block power controller gives me less issues when DCC is on.

As for running MTH DCC, only PS-3 equipped locomotives will work.  RailKing locomotives do not have a switch, but the manual does say how to switch them from DCS to DCC via a jumper.  Premier locomotives have a DCS/DCC switch.

I chose to go to DCC instead of DCS because of PS-3 locomotives, and the number of locomotives I can upgrade (DCC upgrades cost less then PS-3 or ERR TMCC upgrades.).  I wouldn't plan on running Legacy and DCC at the same time.  You can run Legacy and DCS at the same time.  Most O gaugers run Legacy/DCS if they are doing mixed environments.  Most will go full DCC if they do any DCC at all.  I'm weird in that I'm doing switchable between Legacy and DCC.

I fixed it, yes, I did indeed mean DCC.  The fact that TMCC, PS/2, and early Legacy locomotives all choke on DCC powered tracks is enough to nix it for me, I have tons of all three!  I didn't think to test newer Legacy locomotive with the RCMC board as these tests were years ago and I didn't equate the difference at the time.  It's possible that due to the different motor driver architecture of the RCMC that it would run with a DCC waveform on the tracks.  However, that possibility doesn't change the fact that for most people, includeing me, DCC on the tracks would be a non-starter for normal running.

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