Running Multiple Engines in The Same Consist

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fidekel

Canadian Model Railroader
I have always wondered how to correctly run 2 or more DCC's locomotives that are coupled together and pulling a train. Do I run power in both loco's or just one? Does doing this damage the engines due to the difference in power?

Please respond.
 
no, no damage to engines. for best performance they need to be speedmatched and with bemf turned off. but you really want to read up manual of your DCC system on Consisting. exact implementation can vary between makers.
 
If the locos are completely different from different manufacturers, then you have to "tune" them to speedmatch together.

But, in my case, I run 2 of my MTH SD70Ace's and they already run at the same speed, no adjustments necessary.

Press a couple of buttons on my NCE throttle, bam, instant consist.
 


yes what is bemf? I have yet to purchase my DCC system because I havent began building my layout yet. My last layout i used MRC but I sold it with the rest of my stuff.

I plan on getting the Digitrax Zephyr because it is simple and easy to expand.
 
Back-EMF actually reads ther voltage generated by the spinning motor in between pulses of power being sent to it to determine if it is turning at the rate it is being told to turn. Depending on the settings configured, this can be set so that NOTHING will stop the motor from turning short of actually clamping the shaft. Go up a hill, more power is applied to keep it turning at the same speed. Add a dozen cars, more pwoer is added. Go down hill, and power is removed to keep it from speeding up. ESU decoders have this - and they do it very well, as do the other European decoders like Zimo and CT Elektronik. It seems in Europe they are more concerned with maintaining set speeds with no additional throttle control, and so have perfected the BEMF response. Digitrax has BEMF in their 16x decoders, the 12x don't. It works but not nearly as well as ESU's. TCS has BEMF in their decoders and it seems to work very well in my initial test track testing. QSI has BEMF in their sound decoders which works very well.

NCE does not have BEMF in their decoders. Torque Compensation is not the same thing, nor is it a repalcement - it's more of a complimentary feature. When controlling a motor with high frequency pulses (silent drive, supersonic, silent running - each manufacturer calls it something different), the tradeoff for less motor heating and no buzzing noises is less total power, thus less torque, precisely when you need it most - at the lowest throttle positions. Torque compensation applies extra power at low speeds to overcome this. This is usually configurable in decoders that have it - too much and your loco might leap into action, too little and you might still need to advance the throttle more to get it to move but then throttle it back to the actual sustained lowest speed.
 
Back-EMF actually reads ther voltage generated by the spinning motor in between pulses of power being sent to it to determine if it is turning at the rate it is being told to turn. Depending on the settings configured, this can be set so that NOTHING will stop the motor from turning short of actually clamping the shaft. Go up a hill, more power is applied to keep it turning at the same speed. Add a dozen cars, more pwoer is added. Go down hill, and power is removed to keep it from speeding up. ESU decoders have this - and they do it very well, as do the other European decoders like Zimo and CT Elektronik. It seems in Europe they are more concerned with maintaining set speeds with no additional throttle control, and so have perfected the BEMF response. Digitrax has BEMF in their 16x decoders, the 12x don't. It works but not nearly as well as ESU's. TCS has BEMF in their decoders and it seems to work very well in my initial test track testing. QSI has BEMF in their sound decoders which works very well.

NCE does not have BEMF in their decoders. Torque Compensation is not the same thing, nor is it a repalcement - it's more of a complimentary feature. When controlling a motor with high frequency pulses (silent drive, supersonic, silent running - each manufacturer calls it something different), the tradeoff for less motor heating and no buzzing noises is less total power, thus less torque, precisely when you need it most - at the lowest throttle positions. Torque compensation applies extra power at low speeds to overcome this. This is usually configurable in decoders that have it - too much and your loco might leap into action, too little and you might still need to advance the throttle more to get it to move but then throttle it back to the actual sustained lowest speed.

wow thanks great answer.

so after all that which decoders should I use? If I buy an engine that is already equiped with DCC which type of decoder is it? Is it a good one or is cheap and not as good as other ones?
 
I prefer Soundtraxx Tsunami's, they sound great. But QSI revolution's are good too, they have a few more features, but don't sound as good.

If you buy a loco with DCC & Sound already, you need to research on what kind of decoder is installed, and decide if you want to purchase.

You'll figure it out, once you start getting more familiar with DCC locos.

P.S. I got that info off the internet using google. That is not my writing.
 
to put it simply BEMF is cruise control for your engine. uphill or downhill it will try to keep to set speed. if BEMF compensation is enabled ,multiple engines with mismatched speeds will try to compensate for each other - not good. or so i read

it looks like you have the fun task of picking a system in front of you. allow me to offer this advice - look carefully before you buy. play with the systems, compare the tech sheets. otherwise there is possibility you wll be exchanging it soon, (at least i did when i finished studying capabilities of my first system and discovered whats missing.)
Digitrax is respectable system, but its has its peculiarities. i couldn't have lived with those, so i went with nce powercab. not perfect system either but its shortcomings bother me less. in your case it might be different. so look carefully :)

as far as decoders and decoder equipped engines you mostly get what you pay for. if i ever to get bachmann DCC ready again (i actually do like new spectrums) i would factor in cost of new digitrax decoder to replace the factory one right from the start.
general consensus is (and correct me if i'm wrong) to stay away from MRC and bachmann decoders as theit track record is not as reliable, and use NCE, Digitrax, TCS and such instead as much as possible.





EDIT
Motley, can you actually distinguish between QSI and Tsunami? i havent heard tsunami yet but i read reviews saying they a requite comparable, and QSI i do have is darn good (atlas gold dash 8 has 2 speakers they say)...
 
Last edited by a moderator:


EDIT
Motley, can you actually distinguish between QSI and Tsunami? i havent heard tsunami yet but i read reviews saying they a requite comparable, and QSI i do have is darn good (atlas gold dash 8 has 2 speakers they say)...

Yes I have both QSI and Tsunami and I can tell the difference, not a huge difference, but there is, non the less.

Now my 2 MTH SD70Ace's with dual speakers blows the QSI and Tsunami's out of the water.

I guess it depends on what speakers as well.

Also, I recommend the NCE system, it's really newbie user friendly, I was able to learn this system in very little time. And the throttle is top notch, very comfortable, and the thumb wheel is easier to use.

I tried the Digitrax out, and didn't like it. And what's up with that stupid hanging wire on the Digitrax throttle all about? (wireless)
 
I have all HO. You may find it hard to find quality decoders and speakers using N scale though as I have heard.

Yeah I have heard that aswell that was why I was confused when you started talking about sound decoders.
 
I personally like the Tsunami's and QSI as well. Another biggie is the BLI paragon 2.

I have 2 MTH SD70's that I changed to Tsunami's and I think they're better than the MTH when used with the same 2 speakers. The big thing is that the individual sounds can be controlled by the Tsunami but not the MTH unless you get their DCS system.
The paragon 2's I have are excellent. My favorite out of all are the Y6b
Video here: http://www.youtube.com/watch?v=NVj6SGCD7kw
And MTH Berkshire: http://www.youtube.com/watch?v=PSCCBgR6McQ
The others are great as well but lately I've been getting into steamers.
 
I have always wondered how to correctly run 2 or more DCC's locomotives that are coupled together and pulling a train. Do I run power in both loco's or just one? Does doing this damage the engines due to the difference in power?

Please respond.

As to your original question Fidekel, the others have covered the speed matching. Decoders have a method to vary their speed over a wide range, allowing you to fine tune a loco from the slowest speed thru the highest. This allows you to make 2 or more loco's very close to the same over a range. They can be a little off but should be as close as possible.
When you set a consist each loco in the consist gets a different set of instructions. For instance on a 2 loco consist with the first loco facing forward and the 2nd facing backward there would be different settings in each. The front one would have it's headlight on. Engine sounds would work. Horn would work as well as the bell. The rear loco might have all lights dim or rear light on. The engine sounds would work but the horn and bell would not. This is all done through some pretty simple settings.
 
I'm very picky about sound engines. I really like Tsunami, but QSI isn't very good in my opinion. The sounds don't sound very realistic (being around the real thing a lot really tunes my ears to these things). The fact that the QSI has the turbo as a seperate sound and not an integral part of the sound of the prime mover makes it very off, as well as the artificial sounding sounds.

The Paragon 2 sounds ok, although every P2 engine that I have had I was not happy with the running characteristics. The SD40-2s also sound really weird once you get up to notch 5... sounds exactly like their AC6000 which makes me wonder if they recycled their sound files (QSI tends to do that). I know that some of the QSI lovers will tell me that you can buy the quantum programmer and change out the sounds, but my response is: If I am paying so much for a decoder, I expect it to sound great straight out of the package.
 
The Tsunamis are far superior to QSIs or older Soundtrax decoders. They actually sound like real engines.
 
EDIT
Motley, can you actually distinguish between QSI and Tsunami? i havent heard tsunami yet but i read reviews saying they a requite comparable, and QSI i do have is darn good (atlas gold dash 8 has 2 speakers they say)...

Anton, I can. I have both, in both steam & diesel. There are differences in sounds produced, and how they operate. QSI has some features I like better than Tsunami, and Tsunami has features I like better than QSI.

Tsunami does a better 567 engine, and I like their steam chuff better. QSI has neat dynamic brake effects, and their steam unit has cylinder cocks open for the first 15 cycles or so, then they automatically shut off. It all comes down to your personal tastes. I plan to keep my QSI's and would not necessarily order non sound versions of models that would come equipped with QSI. It's a very flexible system.
 


TY for the input Alan. steam is not a concern, not at the moment at least.
from what i can tell, comparing both on youtube, they still pretty close. never heard tsunami live (actually i think thats what the guy in EMRRC had...) but if it sounds "meatier" its a plus as qsi is darn good as it is, and if i happen to get one i will not be neatpicking
 




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