Is there any particular technique to get loco's to run more smoothly at the slowest speeds? Or is this more a function of the specific decoders being used?
Clean track and clean wheels make for the best slow speed operation. Also some locomotives are geared for slower speeds.
j.........
Yes, it depends on the decoder in many cases. The LokSounds are known for being darn good at default settings (most motors), and their Select manual describes how to tweak as needed, or trial BEMF values for some less common motor types, or a auto setting procedure that adjusts to the loco.
Here's some links that I printed out for general info with some specifics by manufacturer.
http://www.sumidacrossing.org/ModelTrains/ModelTrainDCC/DCCDecoders/BEMF/
https://sites.google.com/site/markgurries/home/decoders/decoder-motor-tuning/soundtraxx
http://cs.trains.com/mrr/f/744/p/210416/2303955.aspx
https://tonystrains.com/dcc-motor-control-with-back-emf-and-p-i-d/
https://sites.google.com/site/markgurries/home/decoders/decoder-motor-tuning
Paul
Modeling HO with a transition era UP bent
As was said, depends a lot on the decoder, sometimes how the loco runs.
All decoder manufactures have their CV list online. It can take time. This is the digital age. Many know this.
If you have many locos, JMRI DecoderPro and a computer can make it a lot easier and store your settings if you have to do a reset.
Google JMRI DecoderPro if interested.
Yahoo Groups has forums for different decoder brands and many post their results for different locos, decoders but even that can vary.
Post Scale, loco brand, decoder brand, factory decoder or decoder you added.
More details are needed.
Rich
If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.
Something else to realize. Bachmann locos have a filter circuit in their locos, tenders required by the UK and EU. Two inductors and anywhere from one cap to maybe three caps. Remove the caps. Some caps are a yellow blob. Some are surface mount on a PC board with the inductors. They will have a C prefix.
Some think the two green inductors are resistors. Without the caps, they are a moot point.
They can affect slow speed response with some decoders.
Definitely agree about snipping off the caps. You won't miss them and the loco will run better -- although that a relative term with the "free" Bachmann decoders based on my experience with them in 70- and 44-tonners in HO.
Yeah, lots of variation in the options available in specific decoders. Check the documentation to find out details.
One thing not yet mentioned are speed curves or tables. These are very common and allow you to tailor the loco's response. If you set-up JMRI DecoderPro, it let's you graphically shove the speed curve around in a customizable way that's sometimes easier to grasp than all the CV values you'd otherwise have to parse. Many decoders also feature multiple optional speed tables, which can be tried, too.
Mike Lehman
Urbana, IL
I'll add my vote for for clean track and clean wheels. Along with that, making sure that all wheels are transmitting power to the decoder, with no flaky connections. Make sure every section of track has solid, reliable power, and all frogs and points are solidly powered, too.
It takes an iron man to play with a toy iron horse.
If it's an older loco, disassemble the shell and lube the gear casing and oil the bearing (with plastic capatible oil.) If it's really old, check the gearing for dried up greese! Clean it with a toothpick.Next clean the pickups and track. 70% ISO-Alcohol soaked on a paper towel works. Lay it between track and wheels and hold the train there as it runs.If your train still isn't running the best....1. Check the quartering and make sure it's correct on steam engines2. Check the drive line to see if anything is binding.3. Watch the wheels as they slowly turn to see if they are lobing,uneven,wobbling
Torque is your friend. Torque increases with track voltage. But don't exceed 14.25 Volts DCC. If it's an older open frame motor, consider replacing the magnets. Or replace it with a good quality 5 pole can motor.
The BEST low speed control I have found are in this order:1. Lenz Silver/Gold (non sound)2. ESU Loksound3. QSI (Requires fiddling with lots of CVs. I recommend the QSI programmer)I know nothing of TCS. So I can't make a recommendation there.
Don - Specializing in layout DC->DCC conversions
Modeling C&O transition era and steel industries There's Nothing Like Big Steam!
You left out Zimo and CT Electronik. Not common in the US, but if you want the absolute finest in motor control... You also pay for it, and good luck fininding someone to help. At least there are many vendors carrying Lenz decoders.
All my non-sound are TCS, and they are right up there. The guy with the big Missabe (Jeff Otto) ore dock layout thinks TCS absolutelt stinks, but I've never had an issue with the jerky operation or sudden jumps like he says he had. They are jerky for about the forst 20 feet of running after a fresh install or reset while the self-adjusting BEMF sets itself up. After that, smooth a Loksound. However, they have skyrocketed in cost since the last batch I bought, so I may just use Lokpilot where I don't need sound - same drive as the Loksounds, and cheaper than TCS.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Hi Arto:
You have probably heard this before, but any locomotive must first run well on DC before putting a decoder in it. Others have already explained the basics of achieving that so I won't repeat the information.
The decoder choice is very important. I have several brands of decoders but all I will buy from now on will be Loksound Selects. To give you an idea of how slow they can run, I have a Grandt Line boxcab with a Hollywood Foundaries BullAnt drive. On speed step 1 of 128 it takes about seven seconds for the locomotive to move from the beginning of one tie to the beginning of the next. It is so slow that the lowest speeds are impractical.
Not all locomotives will run that slow mind you. The BullAnt has a 60:1 gear ratio which I suspect is higher than most. The boxcab also has a keep alive installed. However, all my other locomotives with Loksound Selects run very slowly as well.
You can buy the higher priced European decoders that Randy mentioned but I can't see how there could be any significant improvement in slow speed performance.
Dave
I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!
I tuned the control loop on a Spectrum 2-10-0 per instruction that I found on the Soundtraxx website and it went from being an ok runner to being a very good runner. It was a rather time consuming process but worth it.
Mark
The Lenz Silver 21-pin decoder in my converted to HOn3 Liliput diesel was great right out of the box. Exceptionally smooth, it ran sweet from the get-go once I plugged it in.
markie97 I tuned the control loop on a Spectrum 2-10-0 per instruction that I found on the Soundtraxx website and it went from being an ok runner to being a very good runner. It was a rather time consuming process but worth it. Mark
Mark makes a good point here. Yep, the Tsunami is rather old technology compared to many currently available decoders. And I suspect many of the complaints about its performance involve people that expect plug-and-play perfection and think it stinks because they don't bother to crack open the manual.
And I'm speaking only of the steam version of the Tsunami. The diesel doesn't have DDE, which is what makes the sound magic in the steam Tsunami, although there are a few other tweaks and a decent custom speed table doesn't hurt in terms of getting things rolling smoothly.
Search around and find one of the menus folks use with steam Tsunami's and you'll find that you're not simply stuck with what comes out of the Tsunami box/bag. Yes, you do have to work to get there, but that's part of the fun IMO.
For those who want RTR sound, yep, get something more modern...like the new decoder from Soundtraxx when it arrives in the near future, as I suspect they'll have that covered along with other things that need it after almost a decade on the market for the Tsunami.
Me again:
I just experienced another example of Loksound Select's excellent motor control. I had built a railcar using a very old Mabuchi 3 pole flat motor. The motor came from an old kit that I got on eBay. This is the kit. You can see the motor in the upper right:
When I first applied power using the factory decoder settings the rail car took off like a scalded cat. That was on speed step 1 of 128. I figured that the motor would have to be replaced but before ripping the whole car apart I decided to play with the basic speed curve, CVs 2, 5 and 6. Guess what! After some experimentation the rail car runs very nicely. The final CV values are very low but my point is that the Loksound Select was easily able to contain the monster, as it were. The CV values, if anyone is interested, are: CV2 = 1, CV 5 = 12 and CV 6 = 6.
I think I should ask ESU for a commission, but then I wouldn't be able to post here so I guess I will have to stay poor.
Here is the rail car if anyone is interested:
My method for slow speed creep is sitting the CV start voltage and speed step. I also set the momentum CV..
My advice is to experiment with the performance CVs until you are pleased with the engine's performance.
Larry
Conductor.
Summerset Ry.
"Stay Alert, Don't get hurt Safety First!"
WHAT ABOUT THE WIRES.
What guage are you main bus wires? Ho long are they.
Your locomotive can run on a 30ga wire but you will need more volts to push the amperage through that wire.
If you use a big fat 14ga wire as your bus and limit the drops, (LION USES 18ga DROPS) you can push the necessary current through the system at a much lower voltage.
SOME PRIMNATES HERE have suggest that said LION is all wet. But LION says trains of him work better and run more slowly on FAT WIRES.
Your Wildebeest may vary.
ROAR
The Route of the Broadway Lion The Largest Subway Layout in North Dakota.
Here there be cats. LIONS with CAMERAS
Wow, to have to set the max and mid speeds that low makes me think that motor that kit came with is more of a 3 or 6 volt motor, not a 12V.
Lenz and some of the others have an additional CV that set the motor type - though probably what it does is set BEMF parameters, which you cna do with Loksound using the auto BEMF setup. On those Lenz decoders, it makes a huge difference in motor performance as you change that setting.
Hi Randy:
Here is what the motor looks like:
The only information on it is "Made in Hong Kong" and "MABUCHI".
I got two older identical kits on eBay, and they were definitely HO scale so they must have been intended to run up to 12 volts or more on DC. The motors are obviously not high end, nor were the kits for that matter.
I think a major part of the problem is the gearing. The motor worm connects directly to a very small gear on the axle so there isn't a whole lot of reduction.
Anyhow, as I said, the Loksound Select Micro seems to be handling it just fine. Speed step 1 is a reasonably slow creep. Its not as slow as the boxcab but the speed is fine.
By the way, I tried to do the automatic set up but it didn't seem to change the behaviour. I had to do it three times because the first two attempts ran off the end of the test track (at very high speeds I will add) before the set up was finished.
Arto:
If I can make a suggestion, tell us what specific locomotives and decoders you are working with and we can probably give you much more focused answers.
I've seen that exact same motor, about the same size, too, going by the relative size compared to the small clamp, in a toy I had from the early 70's that used two small N size batteries to drive cars on a plastic slot track (on board power in the cars, a bit bigger than HO slot cars (but not S scale size), and they otherwise free ran around the track). So that was 3V with fresh batteries, and that may have been about half speed for the motor. I'm pretty sure that's not a 12V motor by any means.
Randy:
By the way it screamed down the track I suspect that you are right. I'm going to leave it in place for now because it seems to work OK. However, I don't think I will use the second motor in anything.
Thanks for your input.
Most decoders that do not have BEMF have a 'kickstart' option, because the high frequency PWM, while efficient in an electronic sense that it allows those amazingly small chips to handle 1.5-2 amps without heat sinks, is incredibly poor at low speed torque. The pulses are of such short duration that the motor is mostly coasting. Enter the kickstart option which alters the pulses at low speeds to give the motor more torque at slow speeds.
Decoders with BEMF implement this as part of the BEMF feedback loop - when the decoder is set to make the motor turn at a certain speed, the BEMF measures how fast it actually is turning and adjusts the drive to make it happen. It is very unusual for a BEMF decoder to NOT creep along at speed step 1 with no further adjustments such as increasing the value of CV2 (start voltage). If a BEMF enabled decoder does not start moving on step 1 or 2, don;t adjust CV2, adjust the motor control CVs so that is can creep along first. Once the drive parameters are optimized, then adjust CV2 if still necessary. TCS has automatic adjusting BEMF, ESU Loksound and Lokpilot have an automatic adjustment that you need to trigger (and have enough open track for the loco to take off as it runs through the speed range to calibrate the BEMF).
For decoders like the NCE ones that do not have BEMF, they have kickstart. You need to possibly tweak kickstart as well as CV2 for best slow speed operation. You can probably get a loco to move on step 1 or 2 just by adjusting kickstart, but too strong a kickstart makes for very jerky motion. Smoother operation might be possible with a lower kickstart and higher cv2 - it's a balance to find the best low speed operation.
This is all in the decoder. Despite menus in the throttle, this sort of thing applies to the decoder, and then only to specific ones. There is no standard for what CV controls kickstart.
It would be useful to know what type of loco we are dealing with here. For steam engines, performance is mostly affected by the condition of the motor, gears and other attachments on the drivetrain. Diesels are a bit more forgiving, unless we are dealing with a low quality loco...