richhotrainIt is really a shame that several of the recent threads in this Electronics and DCC forum have been corrupted by replies that provide nothing but misinformation about DCC.
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rrebell ATLANTIC CENTRAL rrebell Kinda wondered as I just hooked up my DCC system and it runs better on DCC at very slow speeds than on DC, ran engines as compatable as I could for comparison and no dual decoder for DC mode. What kind of DC throttle/power pack? Sheldon DC is a tech 2 #2500 by MRC. DCC isba Digitrax DCS 51.
ATLANTIC CENTRAL rrebell Kinda wondered as I just hooked up my DCC system and it runs better on DCC at very slow speeds than on DC, ran engines as compatable as I could for comparison and no dual decoder for DC mode. What kind of DC throttle/power pack? Sheldon
rrebell Kinda wondered as I just hooked up my DCC system and it runs better on DCC at very slow speeds than on DC, ran engines as compatable as I could for comparison and no dual decoder for DC mode.
Kinda wondered as I just hooked up my DCC system and it runs better on DCC at very slow speeds than on DC, ran engines as compatable as I could for comparison and no dual decoder for DC mode.
What kind of DC throttle/power pack?
Sheldon
DC is a tech 2 #2500 by MRC. DCC isba Digitrax DCS 51.
Honestly, I am confused by your original post.
Are we talking about one specific locomotive?
With sound? Without? What are we comparing here?
How a loco runs on DC with no decoder, and how the same loco runs on DCC with a decoder, and how that same loco runs on DC with a dual mode decoder are going to be three different results depending on a number of factors.
A tech2 2500 is niether the best or the worst DC throttle. But decoders use full voltage pulse width modulated speed control when in DCC, so that is generally better slow speed control than "average" DC powerpacks.
I honestly don't know exactly what circuitry is used in a dual mode decoder running on DC. And I really don't care. I have no plans use them.
But I know this, all my DC locos (no decoders) run very well, with good slow speed, using my Aristo Train Engineer throttles which also use full voltage pulse width modulated speed control.
My absolute slow speed is not always as slow as the best DCC decoders, but it is very close, and very good, and very "stall free" when starting trains.
Based on my own experiances with dual mode decoders, and my extensive use of DCC on other layouts, I don't get this being on the fence thing. Go DCC or don't.
But good DC throttles can and do provide slow speed control similar to DCC, without some decoder in the way............
Being an 'expert' in symantics doesn't also qualify one to describe what Digital Command Control is, how it works, its limitations, its benefits over DC or other systems currently available, or even be intelligible to those attempting to square themselves with the topic. Secondly, it's a system conceived of, designed by, and constructed by...wait for it... engineers. Thirdly, it is the most successful new method of controlling scale model trains, and is at least as popular as the system it replaced still is, that being DC. The manuals imparting operating instructions and information were written by non-symantically expert engineers, God bless their wrinkled little hearts, and are widely understood and shared by users everywhere who are no more symantically expert than their authors.
I wonder what went wrong....
Overmod I'm largely staying out of this, but: 1) PWM for control of permanent magnet motors is done for voltage control, for example as in gregc's diagram immediately preceding. 2) in DCC, this is done entirely by the decoder, following digital commands it receives. The motor is isolated from 'track power' in that mode. 3) The DCC track power is also PWM, for digital logic purposes. (As the LocoFi material alludes, this is a modulation like that of audible Morse, where the duration of 'short' and 'long' pulses chosen to be much longer than usual noise sources are chosen to represent binary states) 4) If it is not obvious by now, the actual PWM in (3) bears no relationship to any PWM in (2). 5) It should therefore be no particular surprise that a power-level PWM signal modulated for motor control, imposed in place of DCC track voltage, will be wrong for anything expecting logic signals. How wrong, might be difficult to predict, but sure as hell into the world of monkeys on typewriters inadvertently sending commands computers might recognize -- and not balancing DC charge transfer across the logic connection. We can get to a discussion of how 'DC compatibility modes' are arranged on decoders; I would be particularly interested in reading actual details. One logical but naive approach would be to bypass the motor leads to track power while arranging voltage-to-voltage conversion and at least keep-alive power that works with whatever other decoder-based functionality is provided in DC operation. If this is done expecting a potentiometer-controlled or minimal-ripple DC voltage, perhaps assuming some superposed signal or AC modulation for 'compatible-with-DC' device control ... there may be problems if interrupted PWM DC is encountered instead. (Not with respect to the motor, which would have to be of a type that would run on the bypassed PWM voltage... oh wait, wasn't there something about coreless motors not doing well on it sometimes...) Now I'll grant you that PWM fine motor control has been a mainstream hobby technology for so long that it would be surprising if commercial manufacturers designed things ignorant of its existence. But it may be easier just to design what is essentially a crude compatibility mode for a 'least common denominator' kind of DC control, and just forbid the wrong kind of fancy DC that causes issues.
I'm largely staying out of this, but:
1) PWM for control of permanent magnet motors is done for voltage control, for example as in gregc's diagram immediately preceding.
2) in DCC, this is done entirely by the decoder, following digital commands it receives. The motor is isolated from 'track power' in that mode.
3) The DCC track power is also PWM, for digital logic purposes. (As the LocoFi material alludes, this is a modulation like that of audible Morse, where the duration of 'short' and 'long' pulses chosen to be much longer than usual noise sources are chosen to represent binary states)
4) If it is not obvious by now, the actual PWM in (3) bears no relationship to any PWM in (2).
5) It should therefore be no particular surprise that a power-level PWM signal modulated for motor control, imposed in place of DCC track voltage, will be wrong for anything expecting logic signals. How wrong, might be difficult to predict, but sure as hell into the world of monkeys on typewriters inadvertently sending commands computers might recognize -- and not balancing DC charge transfer across the logic connection.
We can get to a discussion of how 'DC compatibility modes' are arranged on decoders; I would be particularly interested in reading actual details. One logical but naive approach would be to bypass the motor leads to track power while arranging voltage-to-voltage conversion and at least keep-alive power that works with whatever other decoder-based functionality is provided in DC operation. If this is done expecting a potentiometer-controlled or minimal-ripple DC voltage, perhaps assuming some superposed signal or AC modulation for 'compatible-with-DC' device control ... there may be problems if interrupted PWM DC is encountered instead. (Not with respect to the motor, which would have to be of a type that would run on the bypassed PWM voltage... oh wait, wasn't there something about coreless motors not doing well on it sometimes...)
Now I'll grant you that PWM fine motor control has been a mainstream hobby technology for so long that it would be surprising if commercial manufacturers designed things ignorant of its existence. But it may be easier just to design what is essentially a crude compatibility mode for a 'least common denominator' kind of DC control, and just forbid the wrong kind of fancy DC that causes issues.
I have only tried a few dozen different ones, but I have yet to find a dual mode decoder that will run on my ARISTO CRAFT TRAIN ENGINEER wireless radio throttles which use full voltage PWM control.
As posted above, my non decoder locos all run at performance levels similar to those same models decoder equiped on DCC.
Those cheap Bachmann decoders sold pretty well on Ebay years ago......
ATLANTIC CENTRAL rrebell ATLANTIC CENTRAL rrebell Kinda wondered as I just hooked up my DCC system and it runs better on DCC at very slow speeds than on DC, ran engines as compatable as I could for comparison and no dual decoder for DC mode. What kind of DC throttle/power pack? Sheldon DC is a tech 2 #2500 by MRC. DCC isba Digitrax DCS 51. Honestly, I am confused by your original post. Are we talking about one specific locomotive? With sound? Without? What are we comparing here? How a loco runs on DC with no decoder, and how the same loco runs on DCC with a decoder, and how that same loco runs on DC with a dual mode decoder are going to be three different results depending on a number of factors. A tech2 2500 is niether the best or the worst DC throttle. But decoders use full voltage pulse width modulated speed control when in DCC, so that is generally better slow speed control than "average" DC powerpacks. I honestly don't know exactly what circuitry is used in a dual mode decoder running on DC. And I really don't care. I have no plans use them. But I know this, all my DC locos (no decoders) run very well, with good slow speed, using my Aristo Train Engineer throttles which also use full voltage pulse width modulated speed control. My absolute slow speed is not always as slow as the best DCC decoders, but it is very close, and very good, and very "stall free" when starting trains. Based on my own experiances with dual mode decoders, and my extensive use of DCC on other layouts, I don't get this being on the fence thing. Go DCC or don't. But good DC throttles can and do provide slow speed control similar to DCC, without some decoder in the way............ Sheldon
Also of note I tried to use engines of comparable quality.
Lastspikemike I am not trying to describe DCC as an engineer would. I've read a bunch of that stuff before I made my inquiries on this board, including reading everything I could find on this board. Most remarkable is the complete absence of an intelligible description of DCC for a lay person, I.e. not an electrical engineer.
I am not trying to describe DCC as an engineer would. I've read a bunch of that stuff before I made my inquiries on this board, including reading everything I could find on this board.
Most remarkable is the complete absence of an intelligible description of DCC for a lay person, I.e. not an electrical engineer.
Alton Junction
Lastspikemike I cross examine them in court routinely, read (and understand) their expert reports and so on. It is a digital rendition of FM radio, basically.
It is a digital rendition of FM radio, basically.
huh?
greg - Philadelphia & Reading / Reading
Removed as not relevant to discussion.
A very simple question, not answered as such to my satisfaction in previous posts:
As I understand it, you are comparing the slow-speed performance of an engine running on DCC, controlled digitally via the motor control from the decoder, with the slow-speed performance of the same make and model of locomotive, without any decoder at all, being operated entirely by DC track-voltage control.
No DC compatibility-mode issues at all. And no issues of anything but DC power being applied in the second case... no sound chip, for example, that needs a particular minimum average voltage to start and run.
After this is answered, please repeat exactly what kind of straight-DC equipment you are using for the 'comparison'.
If I was right about the original question, you will be comparing slow-speed performance at the motor between a reasonably 'intelligent' decoder's PWM output and the probably less intelligent but still well-engineered PWM from a good DC speed-control powerpack. If that is the discussion some of the reasons why you see a bit 'finer' control of slow-speed performance from DCC can be taken up in correct context.
rrebellAlso of note I tried to use engines of comparable quality.
I am really interested in the experiment that you performed, and I would love to read about it in more depth.
I wish this thread could stay on an even keel.
-Kevin
Living the dream.
gregc Lastspikemike It is a digital rendition of FM radio, basically.
Lastspikemike It is a digital rendition of FM radio, basically.
Here's the problem. "Layman's terms" to explain a technology too often lead to oversimplifactions and misunderstanding of what the technology is. You can make non-technical explanations of the basic operation of something like DCC< but to actually understand what goes on under the hood - that requires talking in technical terms or you do not get an accurate picture. Words actually mean things to engineers, too. Usually more literally than for non-technical people. Yes, simplification happens - when matching reverse loops with DCC< you are matching phase, no polarity, but many people, myuself included, often use phase and polarity nearly interchangeably. That isn't necessarily being lazy or ignorant - the vast majority of non-technical people may actually know what you mean when you say "polarity" but draw a blank when you say "phase".
As for the OP's actual question:
Same loco, with and without a DCC decoder. Without the decoder, running on a good DC power source that uses PWM, it will behave at least as well as it would on a DCC system using DCC. Using a pure filtered DC, it will run smoothly, but starts and stops will be more abrupt than either a pulsed DC power pack or a PWM DC power pack. I believe it was Linn Westcott that coined the term "stiction" for the combine electromagnetic and mechanical resistence in the loco - the motor and drivetrain. Pulsed power allow breaking the initial friction without a full motor rotation, so it starts slower. Using PWM does the same, but usually even better because the pulses are always at full amplitude.
Fit the exact same loco with a decent DCC decoder, and run it on a DCC system - it will run equally as well. Not likely to run better, unless you tested the DC operation with a vastly inferior power source. DCC isn't a magical fix for a poor running loco - if it runs poorly on DC, it will run poorly with DCC. Highly unlikely for the reverse - that it runs well on DC but poorly on DCC. The difference with DCC is that since the 'throttle' portion is onboard the actual loco, you can adjust the loco's response to the physical throttle you hold in your hand in ways you just can't with DC. At least not with commonly available DC power packs - back in the day there were some pretty fancy ones that had start voltage, max voltage, pulse width, pulse strength, and pulse duration settings, and other things. So you COULD tweak the control to the loco. The downside to that is, you have to readjust it for each loco.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
rrebell ATLANTIC CENTRAL rrebell ATLANTIC CENTRAL rrebell Kinda wondered as I just hooked up my DCC system and it runs better on DCC at very slow speeds than on DC, ran engines as compatable as I could for comparison and no dual decoder for DC mode. What kind of DC throttle/power pack? Sheldon DC is a tech 2 #2500 by MRC. DCC isba Digitrax DCS 51. Honestly, I am confused by your original post. Are we talking about one specific locomotive? With sound? Without? What are we comparing here? How a loco runs on DC with no decoder, and how the same loco runs on DCC with a decoder, and how that same loco runs on DC with a dual mode decoder are going to be three different results depending on a number of factors. A tech2 2500 is niether the best or the worst DC throttle. But decoders use full voltage pulse width modulated speed control when in DCC, so that is generally better slow speed control than "average" DC powerpacks. I honestly don't know exactly what circuitry is used in a dual mode decoder running on DC. And I really don't care. I have no plans use them. But I know this, all my DC locos (no decoders) run very well, with good slow speed, using my Aristo Train Engineer throttles which also use full voltage pulse width modulated speed control. My absolute slow speed is not always as slow as the best DCC decoders, but it is very close, and very good, and very "stall free" when starting trains. Based on my own experiances with dual mode decoders, and my extensive use of DCC on other layouts, I don't get this being on the fence thing. Go DCC or don't. But good DC throttles can and do provide slow speed control similar to DCC, without some decoder in the way............ Sheldon People need to read carefully and not interpit. One layout with pigtails so I can switchn out power supplys (layout only half finished wiring so these are my test leads). Two different power sources, one DC one DCC, two engines, one DC only, one DCC and sound only. No dual decoders, never mentioned except to say this (unless I screwed up on my typing, using a less than user freindly laptop).
People need to read carefully and not interpit. One layout with pigtails so I can switchn out power supplys (layout only half finished wiring so these are my test leads). Two different power sources, one DC one DCC, two engines, one DC only, one DCC and sound only. No dual decoders, never mentioned except to say this (unless I screwed up on my typing, using a less than user freindly laptop).
OK, no matter what you think is comparable quality, if they are different brands and different models, your comparison of their performance is meaningless, it is apples and oranges.
There is no baseline of comparison because you do not know if the DC loco would run slower/better on DCC? It might not. You don't know how good or bad the DCC loco might run on DC - with or without a decoder.
You don't have enough data to conclude anything.
I have a large and varied fleet of good quality DC locos, I have pulse width modulated throttles, and I have some locos that run better than others. But ALL OF THEM run better than they run on some mid grade power pack - because of the superior PWM control of my Aristo throttles.
And all my friends with DCC have similar varied fleets of locos, and some run better than others.
It is not clear to me that the two locos are same make and model?
LastspikemikeThe DCC signal varies in frequency. That's how it works.
Moreover, the DCC signal uses a square waveform, with the necessary allowance from 'ideal' compensated for (admittedly this is hidden in the engineer-speak in the standards definition to correct for any normal deviation from 'ideal' due to real-world risetime and decay and some of the 'ringing' artifacts, and of no practical interest to actual users other than it makes the assumption of 'square wave' real-world practical.)
FM is frequency modulation.
The other option would be to vary the amplitude, voltage modulation. That would be an AM solution to the problem.
When you read a good introduction to the development of the DCC standard you will find that various forms of digital-via-AM were considered but rejected.
Just because FM and AM refer to specific radio signals doesn't make those specific terms inapplicable generally.
Often the expert cannot see the simple stuff.
ATLANTIC CENTRALIt is not clear to me that the two locos are same make and model?
He also specified both his DC and DCC control and power equipment, although I don't know enough about the specific DCC equipment to tell what difference that might make to his 'decoded' low-speed 'fidelity' or responsiveness.
Here is the PDF manual for the Tech 2 2500:
https://www.modelrectifier.com/v/vspfiles/resources/dc-ac/Tech%202%202500%20AF130.pdf
My understanding is that this does speed (and braking and momentum simulation) entirely in the voltage domain, but with 'pulsed' additional voltage boost (at nominal 60Hz fixed frequency) at times. (I am amused that in the power domain this appears to correspond to a kind of 'amplitude modulation' to get a load moving...) It does not mention anything about PWM being used to produce either the voltage control or the additional-voltage pulses.
The slow-speed performance from a good modern decoder will have some additional control both over the delivered PWM 'voltage control' and by reading the back EMF from the motor. I would not at all be surprised to find the slow-speed regulation 'better' on DCC for a given drivetrain BUT I'd also expect that the best smoothness vs. performance might require quite a bit of tweaking and optimization, some with poorly or inadequately documented CV settings that may influence each other.
Overmod Lastspikemike The DCC signal varies in frequency. That's how it works. That's not at all how it works.
Lastspikemike The DCC signal varies in frequency. That's how it works.
That's not at all how it works.
Since we have two separate conversations traveling on parallel tracks and the discussion on explaining DCC in "non-lawyer" terms keeps pushing the OP's thread to a siding, how 'bout someone start a separate thread on the former. So, from this point forward all posts will be relevant to rrebell's question on his DC/DCC locomotive experiment and any competing conversations will be relegated to the scrap yard - Thanks.
Tom
https://tstage9.wixsite.com/nyc-modeling
Time...It marches on...without ever turning around to see if anyone is even keeping in step.
tstagehow 'bout someone start a separate thread on the former.
Overmod ATLANTIC CENTRAL It is not clear to me that the two locos are same make and model? It was my understanding that he took pains to get the two locomotives as 'alike' as possible, other than one being DCC with decoder and the other 'pure DC' to the motor. He also specified both his DC and DCC control and power equipment, although I don't know enough about the specific DCC equipment to tell what difference that might make to his 'decoded' low-speed 'fidelity' or responsiveness. Here is the manual for the Tech 2 2500. My understanding is that this does speed (and braking and momentum simulation) entirely in the voltage domain, but with 'pulsed' additional voltage boost (at nominal 60Hz fixed frequency) at times. (I am amused that in the power domain this appears to correspond to a kind of 'amplitude modulation' to get a load moving...) It does not mention anything about PWM being used to produce either the voltage control or the additional-voltage pulses. The slow-speed performance from a good modern decoder will have some additional control both over the delivered PWM 'voltage control' and by reading the back EMF from the motor. I would not at all be surprised to find the slow-speed regulation 'better' on DCC for a given drivetrain BUT I'd also expect that the best smoothness vs. performance might require quite a bit of tweaking and optimization, some with poorly or inadequately documented CV settings that may influence each other.
ATLANTIC CENTRAL It is not clear to me that the two locos are same make and model?
It was my understanding that he took pains to get the two locomotives as 'alike' as possible, other than one being DCC with decoder and the other 'pure DC' to the motor.
Here is the manual for the Tech 2 2500. My understanding is that this does speed (and braking and momentum simulation) entirely in the voltage domain, but with 'pulsed' additional voltage boost (at nominal 60Hz fixed frequency) at times. (I am amused that in the power domain this appears to correspond to a kind of 'amplitude modulation' to get a load moving...) It does not mention anything about PWM being used to produce either the voltage control or the additional-voltage pulses.
Correct, the Tech 2 does not use PWM, I don't think MRC has ever built a PWM throttle of any kind.
Most of their products in recent decades have been simple transistor throttles, with various features, braking, momentum, pulse power.
Sometimes the pulse power, typically just half wave DC, fades into full DC as the voltage increases.
I long ago stopped following the details of each of their products.
Yes, many/most decoders now use BEMF to improve motor smoothness. It is the reason some locos perform slightly better with DCC than they do on the Aristo or other DC PWM throttles.
I have found these differences so small, and often in consistant, so as to not be important to me.
I have also learned variations in factory "DCC ready" light boards can effect DC performance. Sometimes the light boards are a plus, sometimes not.
And locos like Bachmann have noise circuits that must be defeated for best performance, DC or DCC.
Just my view, but to restate - any minor difference between the performance of any given loco with no decoder on a top quality PWM throttle and that same loco with a premium DCC decoder, is so small as to not be consistantly measurable or of any practical importance in actually operating a layout.
That is the goal after all, to run trains.
Having no interest in onboard sound, I am very happy with DC control.
Just curious, long ago in the 1980's I think they used to sell regearing kits so you could change the gearing ratio on some locomotives to get them to run slower or smoother. Basically by changing the gearing ratio the engine drive spins faster but the wheels move slower. Do they still sell those kits? Just curious.
CMStPnPDo they still sell those kits? Just curious.
We almost lost them but Northwest Shortline is the go-to source for drive-line parts.
https://nwsl.com/collections/regearing-repower-kits
I had contemplated getting their gear set to increase the speed of the old Life-Like Proto 1000 RDC but in the meantime Rapido produced some "quicker" designs.
Regards, Ed
gmpullman CMStPnP Do they still sell those kits? Just curious. We almost lost them but Northwest Shortline is the go-to source for drive-line parts. https://nwsl.com/collections/regearing-repower-kits I had contemplated getting their gear set to increase the speed of the old Life-Like Proto 1000 RDC but in the meantime Rapido produced some "quicker" designs. Regards, Ed
CMStPnP Do they still sell those kits? Just curious.
I think he might be refering to the old Ernst kits to regear various Athearn Blue Box locos?
They also offered a gear conversion for the Athearn RDC.
I try to avoid 80' long passenger equipment, so I like Athearn's selectively compressed RDC.
If I remember correctly, the original Helix Humper was a regearing kit for things like steam locomotives with a worm on the motor shaft and a bull gear on a driver axle. The kit used a humongously larger-diameter multiple-start worm and a bracket arrangement that tilted the replacement motor up to fit.Could that be the 'kit' you were remembering?
Overmod If I remember correctly, the original Helix Humper was a regearing kit for things like steam locomotives with a worm on the motor shaft and a bull gear on a driver axle. The kit used a humongously larger-diameter multiple-start worm and a bracket arrangement that tilted the replacement motor up to fit.
If I remember correctly, the original Helix Humper was a regearing kit for things like steam locomotives with a worm on the motor shaft and a bull gear on a driver axle. The kit used a humongously larger-diameter multiple-start worm and a bracket arrangement that tilted the replacement motor up to fit.
Yes, and they also sold can motor kits for Athearn locos. In my RDC shown above, the motor came from Helix Humper, the gear kit from Ernst.
ATLANTIC CENTRALCorrect, the Tech 2 does not use PWM, I don't think MRC has ever built a PWM throttle of any kind
I was under the impression that the MRC Tech II 2500 produced a PWM output.
CMStPnPJust curious, long ago in the 1980's I think they used to sell regearing kits so you could change the gearing ratio on some locomotives to get them to run slower or smoother. Basically by changing the gearing ratio the engine drive spins faster but the wheels move slower. Do they still sell those kits? Just curious.
They come up on eBay fairly frequently. Usually the sell in the $5.00-$10.00 range at auction, but people sell them at $25.00 and up for Buy It Now.
I only installed one Earnst Super-Gearing kit is an Athearn SW switcher. Then it was just a little noisier and much slower. It was a good improvement for a switcher.
I guess the only way is if I used the exact same engine. That will not happen and after futher testing of just DCC engines, I have two exact ones of the same engine, one runs twice as good as the other and I can find no diferences that would make it so.
SeeYou190 ATLANTIC CENTRAL Correct, the Tech 2 does not use PWM, I don't think MRC has ever built a PWM throttle of any kind I was under the impression that the MRC Tech II 2500 produced a PWM output. CMStPnP Just curious, long ago in the 1980's I think they used to sell regearing kits so you could change the gearing ratio on some locomotives to get them to run slower or smoother. Basically by changing the gearing ratio the engine drive spins faster but the wheels move slower. Do they still sell those kits? Just curious. They come up on eBay fairly frequently. Usually the sell in the $5.00-$10.00 range at auction, but people sell them at $25.00 and up for Buy It Now. I only installed one Earnst Super-Gearing kit is an Athearn SW switcher. Then it was just a little noisier and much slower. It was a good improvement for a switcher. -Kevin
ATLANTIC CENTRAL Correct, the Tech 2 does not use PWM, I don't think MRC has ever built a PWM throttle of any kind
CMStPnP Just curious, long ago in the 1980's I think they used to sell regearing kits so you could change the gearing ratio on some locomotives to get them to run slower or smoother. Basically by changing the gearing ratio the engine drive spins faster but the wheels move slower. Do they still sell those kits? Just curious.
I don't think so. It is not a true full voltage pulse width modulated throttle.
With true PWM, all voltages applied to the track are full voltage square wave pulses, which start out widely spaced and become longer in duration to increase speed.
The MRC instructions say the pulse rate is 60Hz, and that the pulses disapear as speed increases as I described above.
That is not PWM, which uses much higher frequencies (more rapid pulses).
Example, with my Aristo throttles, the headlights of DC locomotives light up at nearly full brightness before the loco even starts to move, because of the full voltage high frequency nature of the pulses.
PWM is a long time well known way to control DC motors, if they were using it, they would call it that, rather than making up their own new name, "proprtional tracking control", which by description is just old fashioned half wave pulse power that turns off automaticly around half throttle.