Multiple trains on a single mainline. Each easily independently controlled from one throttle. Do that with DC with a control panel and wiring that would make a NASA control room look like kids play !!!! Two trains traveling opposite directions on a single mainline. One train gets put in a siding. The other passes by. The train in the siding gets back on the main again in the opposite direction of the other. Advantage: No flipping hundreds of switches on block control to get that scenerio accomplished ! Thats just a couple off the top of my head that I do on many an occasion.
Actually I like that type of scenario. It really makes the crew operate their trains. Like old timetable and train order, dark territory days.
Although, my layout still sports Cab A and Cab B, Analog DC I can switch over Cab B to DCC and it's everything George said it would be. That's why you'll hear me say "If" I was starting out all over again...and you know the rest. George is right my control panel looks like the NASA control room on steroids. However, that's what I have and I will stick with my Momentum powered, power packs or are they called transformers? I had a train car that would turn into a monster of some sort when it ran over a dead spot and some kind of flying machine when it shorted out. Is that a transformer? Anyway, no intent here to hurt anyone's feelings. I gave my advice and you can take it any way you want to. Remember it's your railroad, you make the rules and you set the standard. When you do that no one can insult you. Why? Because it's what you want. Salute!. Go have some fun but do send pictures so we can see how much of a flop it was...Uhh...Err...I mean how much of a success it is. Now go out there and build what you want, power it up anyway you want and ignore everything you've been told. What? What? What did I just say? Till later.:wideeyes::teeth:
You could build your own: http://www3.sympatico.ca/kstapleton3/851.HTM Or does this apply? https://www.yahoo.com/makers/young-people-dont-know-how-to-fix-anything-106523138575.html Al
Thank you for the replies and information so far. Guys DCC simply is not in the budget yet. Next month I have to fork out for our portion of a wedding. Then I have two trucks and a horse trailer needing new tires. Then there are some long overdue honey-do's to the house. I got the final pieces of my track yesterday and the layout is complete. Next step is to build the table and glue the foam down (probably this weekend as it is forecasted to be a rainout). Then I can start reassembling everything and work on the fun stuff like roadbed, buildings, etc. My layout has lots of switching action so one locomotive will keep me occupied for a long while. Hopefully my new Atlas GP7 will be up to task..
DCC does cost some money. It's surprising how many people assume everyone else out there has the same budget or spending abilities. Nothing could be further from truth. As long as the individual is happy, that's what the whole point is for a hobby.
I agree. I would probably still be on DC if it hadnt been for the accident settlement $$ that came in just as I was planning on rebuilding the layout
Hmmm. Gotta think about this one. Maybe I should sue the grocery store for injuries caused when I was attacked by a rogue potato chip? That should pay for a few new trains...?
Here's my brain dump on this subject. Part 1: Nearly every DC throttle made, from the 1970s to today, uses pulse power. They may not say it anymore (probably because the word scares people), but you put a scope on the output of that throttle, and you'll see that it is most certainly not a smooth DC output. That Tech 7 that "doesn't mention pulse" mentions "slow speed running", and indeed, it uses pulse. Even nice modern 5-pole motors run much better with some pulsing in the supply. Even the coreless beauties that I run in my rebuilt engines can be coaxed to get the the train moving at a bit slower and steadier speed with some pulse turned on. This page is very enlightening: http://www.sumidacrossing.org/PhotoAlbums/ElectricalSystemsPhotos/DCTestingPhotos/ He tested a ton of throttles, put an oscilloscope on their output, and showed you what the throttles actually do (nevermind what anyone CLAIMS they do). And they aren't all old ones. Look around on his site and you will find a review of one of the Tech 7's, and he shows that they also use a pulsed waveform. ------------------- 2. Pulses from years ago aren't like pulses now The fear and hatred toward pulse power comes from the *type* of pulses used in throttles designed for big, tough motors used in HO and larger scales long ago. Pulses were often high amplitude brutal square waves that are great for getting big indelicate motors moving at low speeds, but make for a lot of heat, noise, commutator pitting, and other terrible things. But that doesn't change the fact that when pulses are done right, motors run beautifully on them and will not be harmed. ---------------------- 3. What do you buy? The original poster wanted recommendations on a DC pack that would be inexpensive, would perform well, and won't harm motors. I would stay away from the MRC Tech II 2500 because I have played with those and the pulses are pretty strong and brutal for my taste and cannot be turned off. They do make engines run well, and the pulses dimish automatically as you raise the speed, but I found the pulses to induce a lot of noise in the motors and they seemed to be much stronger than is necessary. Prolonged running at low speed will mean harsh pulses all the time, which I do not like. When people say modern motors don't need pulses anymore, they may not realize it, but what they mean is that modern motors don't need THOSE NASTY pulses anymore. You still need pulses for really good low speed running, and that's why all the throttles still use them. DCC decoders are driving the motors on PWM, a very nice type of pulse indeed. ----------------------- The Kato pack (reviewed on that site I mentioned above) is very popular. There's almost nothing inside it. All it does is feed the pulsing rectified DC to your motor. But surprisingly, THIS ISN'T SUCH A BAD IDEA! As it turns out full or half-wave rounded pulses are quite kind to electric motors and do a pretty good job of making them move at lower speeds. So if you're looking for something simple and safe just to run your trains, that would be a good one. I REALLY like the idea of building one yourself. The Stapleton throttles look like really nice designs and are priced low: http://www3.sympatico.ca/kstapleton3/851.HTM (I have never actually owned one, however). These use PWM (pulse wave modulation) to get you good slow-speed running. They are square waves, but this is quite different from the square waves I was bashing above. The amplitude is under control, and they idea is to increase the frequency and width of the pulses to control the speed. PWM is how DCC decoders power your motors. $45 bucks, assembled, seems like a good deal to me. In the $30's if you build it yourself. ---------------------- They key is to use controlled, gentle pulses. They will make your motors run better without heat or damage. So, what do I use? I use a home-made transistor throttle I built from a 1970s circuit book, and I have used it ever since. I built several others over the years with different pulse designs, but never liked any of them, or any commercial throttle I tried, better than that old home-made one. It uses smooth DC with half-wave pulses riding on top of the smooth output, and I can turn the pulses on or off if I wish, but I never turn them off. But if I were buying something right now, I'd try one of those Stapleton throttles
Notice he says "I have brought[sic] a Atlas GP7 that says it is both DC and DCC." That means the engine already has a decoder in it. While pulsed power will not harm a decodered engine, the engine will run better on smooth DC power, especially at really low speeds. I especially would NOT get a PWM power pack. Again, they will not harm anything, but as far as running they can be worse than a pulsed power pack. A well designed decoder would never confuse the relatively low frequency of pulses that most "pulse" power packs use with a DCC signal; however, if they are in the right frequency range it could confuse the typically higher frequency pulses of a PWM throttle with a DCC signal.
CSX Robert makes an excellent point. It looks like I (and others) missed that comment in the original post - that this engine already has a decoder in it. I am sorry for that. Yep, the PWM throttle can cause trouble there, so I guess that option is out.
In order to be most effective, however, the pulses must be of low enough frequency (around 60 - 120 Hz) to "vibrate' the motor into turning sooner. This is unlikely to "confuse" a decoder into "thinking" it's getting a DCC command. I do agree, however, that pure DC is the best to feed a decoder since that's what it really wants to see to create its output. The old MRC packs like the Throttlepack 500 have pulse power created just by half-wave rectifying the AC voltage and the waveform is still sine-wave in nature. It's just that there are only positive-going peaks instead of positive-negative-positive-etc. Modern pulse generators can be almost any waveform you want and the output of most decoders is square-wave in nature although not exactly a square wave. Different waveforms and duration, amplitude, have varying effectiveness on any given motor. Originally, pulse power, probably more than reducing cogging, was meant to overcome friction in mechanisms from years ago when it was much higher than in today's low friction locomotive mechanisms. That's why pulse is not needed as much as years ago. However, it still can make a locomotive perform better at super slow speeds. It's just a matter of preference, really, as to how slow you want to operate your trains and reliably at those low speeds. And, like I said before, overheating of a motor is more due to carelessness in disregarding load caused by friction in motor bearings, drive mechanisms, wheel bushings, etc. than it is from pulse power. I have many old N scale locomotives that have operated on pulse power many, many times and still run like new to this day. EDIT: After reading CSX Robert's post more carefully, I see I repeated some of what he said. I guess it's good we agree. Doug
Let's see if I can remember this correctly. A friend of mine who deals with electronics said of much of the older technology, "Those that continue to mess around with it are only asking for trouble". You'll forgive me for being a skeptic. There is a difference between pulse and momentum. The signal and wave are different. So I won't buy into the above statements. Saying once again it's easy to be confused about the difference between pulse power and a transistorized throttle with momentum. To categorize it as being the same. I don't think so. I remind you to take what you want from here and leave the rest behind. Now where's my shovel it's getting deep in here.
A person could use the John Allen G&D solution use a electric motor to spin a large flywheel equipped generator to make track voltage. The flywheel would create a momentum and braking effect on the engine. If a anybody tries this let us know.But to be serious ,I have not had any problems with my daul mode DCC engines with any transformers with the pulse turned off or newer so call non pulse units.(basic Bachmann,kato packs)
Why do you keep bringing up momentum? This thread is about pulse, not momentum, and as far as I can tell, no one in this thread has confused pulse and momentum.
