DCC vs. DCX

DCS and DCC is like apples and oranges. DCS uses a modulated carrier while DCC is essentially baseband communication. DCC is a variable pulse width alternating polarity DC signal. So, it's actually AC, but not a sine wave. How MTH conditions and reads the DCC signal (that can be noisy, due to electrical motors, etc.) will determine how well the locomotive performs. De-modulating the DCS signal is completely different.

Hi Oman, thanks for the reply!  So what you are saying is the MTH locomotives that are advertised as DCS/DCC are not "true" DCC decoders which is why I may be having issues while the Atlas and Weaver stuff that have "real" DCC decoders in them are ok because they do not try to be a jack of all trades?  Makes sense in a way but it is kind of sad that I may have to use two different systems (not simultaneously of course) to get the most out of my trains.

There are key words when considering DCC decoders, one "Compliant" which means full NMRA implementations, and "Compatible" which means whatever the mfg decided to include.    

Generally the compatible decoders give you problems with changing sound features and other finer details, not with running.     Our local club has a number of issues with compatible decoders not behaving as well as expected and they run NCE also.

However, y ou still may have more of a track problem than decoder problem, if it is just running issues, not sound or other feature programming.

A hesitation or lurch implies a break in contact, which may be the track or dirt on the wheels.    I would look at the wheels carefully and see what you can see.    Do it under good light.    also look at the track.  

If the locos run OK on part of the layout and not others, that is a clue that it may be a track problem.

@Cadillac Mike posted:

Hi Oman, thanks for the reply!  So what you are saying is the MTH locomotives that are advertised as DCS/DCC are not "true" DCC decoders which is why I may be having issues while the Atlas and Weaver stuff that have "real" DCC decoders in them are ok because they do not try to be a jack of all trades?  Makes sense in a way but it is kind of sad that I may have to use two different systems (not simultaneously of course) to get the most out of my trains.

Mike

I'm not a DCC expert, but as an electrical engineer, I know about baseband communications. I would think that each DCC decoder uses (maybe similar) different techniques for determining the 1's and 0's. So, I wouldn't say that the MTH decoders are not real decoders. However, as suggested above, your problem could be related to an electrical continuity issue. Conditions that affect the DCC signal may not be a problem to the DCS signal.

Thanks guys.  I will double check that everything is still good regarding the track.  I use a "bright boy" to clean the rails.  If anyone has a better solution please let me know.  I have heard Wahls hair clipper oil actually helps with conductivity but I have never used it.  I was always afraid to put oil on the rails but at this point I will try anything so I can run the steam locos on DCC.  I want to run all my brands at the same time, not sit the Atlas on the shelf while MTH is on the rails and vice versa.

In the past I've used Zap Rail-Zip. That was for a carpet layout. After putting my track on benchwork, I haven't required it.

I am by no means an expert on 2 rail pikes being a 3 railer. I have an 0-8-0 switcher that can be 2 railed by removing the rollers and throwing the switch. Seeing 2 rail involves insulated wheels. On a steamer. With blind drivers as well as traction tires. How good are the MTH engines as far as electrical pickup from the 2 rails versus a traditional 2 rail steamer ?

Hi Dave!  I really love what MTH did with the 2/3 rail convertible steamers because I have pretty tight curves for a "scale" layout and would be relegated to small switch engines and traction equipment if not for the blind center drivers on Mike's Train House stuff.  The wheels on MTH gear are MUCH wider than traditional scale wheels so that may help negate the traction tires which hinder pickup. This may be part of my issue though as the stuff that runs well on my pike is all made specifically for 2 rail and has pickups on every wheel.  I use vintage Atlas track and the flanges of the MTH gear does not interfere with the frogs but I could never get away with trying to run the stuff on modern Atlas or other 2 rail track.

@Dave_C posted:

I am by no means an expert on 2 rail pikes being a 3 railer. I have an 0-8-0 switcher that can be 2 railed by removing the rollers and throwing the switch. Seeing 2 rail involves insulated wheels. On a steamer. With blind drivers as well as traction tires. How good are the MTH engines as far as electrical pickup from the 2 rails versus a traditional 2 rail steamer ?

That's a good point. I have a 22- MTh diesel, that came equipped with scale wheels. Out of the box, it ran fine as a 2 rail model. Then, I installed the hi-rail wheels (traction tires) and again ran it as a 2 rail model. It kept stalling. The last step was to add the pick-up rollers. Once running 3 rail it was fine.

We may be onto something here.....  The MTH 2/3 convertible  stuff is GREAT on DCS but if one wants to run specifically on 2 rail DCC, one should probably go the "scale wheel" route.  With 20" radius (40" diameter) that is going to limit my options for steam locos I suppose.  Oh well, mama bear thinks I have enough stuff anyway.  She is probably right but I would never admit it.  

I'm also a 3R guy, but I run my MTH locos in DCC on 3R Atlas with the same 10amp setup.  I don't have any steamers, but I do have 3 diesels, 2 are the Premier 2/3 rail locos in 3R config.  They are very picky about electrical pickup on the wheels.  Mine kept stalling too, but the center rail rollers were on good rail.  Took me a while, but I figured out that it was the wheels were not making good contact to the outside rail on one side (I use new Atlas 3R track and did not tie the outside rails together so I could do signaling.).  I had to rewire my loop to use the other rail for return, since then they have run fine.  I can't imagine how frustrating it would have been if I had to use the wheels for pickup and return.  So I would for sure look at how well the wheels are contacting the rails.

Update- a good cleaning of the locomotive wheels has solved the issue.  Evidently, the forward set of drivers seems to be the best source of electrical pickup when running MTH steamers on 2 rail.  I put the locomotives in the cradle, hit the drive wheels with the Kadee wheel cleaner (this is a great tool for 2 railers), put everything back on the track and GREATLY enjoyed seeing my Western Maryland H-9 and L&NE (Ex PRR) L1 run like new.  Thanks to all for the assist!

Enjoy your trains this autumn!

Mike