Hi all,
My first post, so I hope I'm posting in the right place. Please forgive me if I call something the wrong thing--I'm not fimiliar with all the model railroad jargon. I'm in the process of going through and thoroughly cleaning all my locomotives after being out of the hobby for a number of years. I have a digitrax DCC system using a DCS-100 and a DT-400R throttle that was purchased used on eBay. I am doing the following for each locomotive I'm cleaning:
The problem I'm having is that at slow speeds, and sometimes at higher speeds, the locomotives seem to lobe. To best describe, it's almost like its hitting a tight spot either in the motor or the gears, and it slows down for a second, before speeding back up. This issue seems present both before and after cleaning the locomotives, but I thought it was just a dirt issue before I started cleaning. I know that the engines are getting good power--the lights on them are bright and strong throughout the whole layout and do not flicker. I have 15 volts on the track across the whole layout (note that I intentionally increased the voltage to 15 volts since I'm running some older locomotives). The engines in question are using a mix of Digitrax decoders, and model brand decoders. I have 2 engines running Digitrax decoders, a Bachmann running its own decoder, and a Broadway Limited with its Sound Decoder. All seem to display this issue, though the intensity of it varies engine-to-engine.
My question is two-fold:
1. Am I doing something wrong in my cleaning process that may cause this?
2. Could this be a DCC setting issue? I've tried factory resetting the DCS-100, setting it to 128 step FX mode, and setting decoders to 128 step mode. It did not seem to make a difference.
Thanks in advance for any help!
To me, that has all the hallmarks of a cracked-gear problem (q.v.). There are other things that can affect steam engines -- you don't say how many of yours are -- that can be adjusted.
You might list the precise 'culprits' for more directed advice.
First, welcome to the forums!
Not being an expert myself, I guess I would check the voltage. You said you intentionally set the voltage up to 15 volts.
Have you tried it at a lower voltage? DCC systems can be pretty touchy about things.
York1 John
Unless I missed it, I don't see what type of engines (steam, diesel, electric) you're using? If steam engines, it could be when you were working on the engines and handling them that you bent one of the siderods or the eccentric rod so that it's hitting each revolution of the wheels.
Welcome JD Tractor! I have a couple myself, garden size that is!
It would help if you could be more specific on what locos you have.
Do they do this at random spots around the layout? or at the same spot, each time ?
Mike.
My You Tube
Thanks for the replies. I will try and answer all your questions in one post rather than replying to all of them.
I have 5 locomotives that are all displaying this issue; I'll list them below.
-Bachmann Steam Locomotive, cheap engine I threw a decoder in, so I can understand the lobing in this one. Has been cleaned.
-Bachmann Diesel with a Bachmann decoder preinstalled. Has been cleaned.
-Athearn Genesis Amtrak Diesel with a new Digitrax decoder installed. Has been cleaned.
-Athearn Genesis BNSF Diesel with a NCE decoder in it now, soon to be replaced with a digitrax decoder. Has NOT been cleaned yet.
-Broadway Limited Imports CSX Diesel with the sound decoder it came with. This is a really high quality engine, which is why I'm kinda stumped that it also exhibits the issue.
All of these engines show this lobing issue, and it seems to be consistent across the entire layout, although again it is worst at slow speed, least noticable at top speed.
None of the engines have had a decoder installed with a light board. As of now, all of the Digitrax decoders I have installed are the DH126D. Those are on the Athearn Amtrak and the Steam engine, and it's just the decoder in there.
Let me know if there's any other details I can provide. Personally I'm hoping it's some sort of a configuration issue...
Am I the only one who doesn't know what lobing is?
In my world lobes are round things like the occipital lobe in your brain. Merriam Webster and I don't recognize the word as a verb. Not trying to be a jerk.
Perhaps you mean lug?
Henry
COB Potomac & Northern
Shenandoah Valley
Thank you, Henry. I was just going to post a similar query. I did google "lobing" but it was an accoustical term having to do with the interference of sound waves coming from two separate sources; not what was being described by the OP.
Tom
https://tstage9.wixsite.com/nyc-modeling
Time...It marches on...without ever turning around to see if anyone is even keeping in step.
I'm sorry guys. By lobing I mean that the locomotive will have minor variations in speed in a pattern. So, in this case, it'll drive normally for about .5 seconds, then hit a patch where it slows up just a tiny bit, but enough that it's noticable, and then in about .2 seconds it gets through that patch and goes back to its normal speed. When it does it repeatedly the engine looks jumpy as it goes around the track. I can post a video of it doing it tomorrow if it would help. Thanks.
I know what a cam is, but none of my diesels have one. But I get the idea, they slow, then speed up then slow.
All 5 engines do it.
Questions: Do they do it at the same place on the track?
How are the feeders spaced?
What DCC system are you using?
Has your layout always been functioning like this or is this new behavior?
I've not had track gauge issues, but i suppose it could be possible.
I figured out what he's talking about is probably more commonly spelled "loping"
There's nothing fromt he system that woudl cause this. Choice of decoders might - and it was coinfirmed - the DH126 has no BEMF, so especially at low speed it's going to have issues with even the slightest bind in the mechanism. In addition, most Bachmann locos have capacitors on the motor which make control worse, even when there is no BEMF.
There is only limited adjustment int he Digitrax decoders without BEMF, but you might want to check that torque compensation is enabled for best low speed operation. The default is on, but it may have gotten changed. CV54 should be either 0 or 1 - bvoth ahev torque compensation but 1 also enables switching speed where turning on F6 halves the top speed and momentum settings for switching.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
rrinkerChoice of decoders might - and it was confirmed - the DH126 has no BEMF, so especially at low speed it's going to have issues with even the slightest bind in the mechanism.
I like TCS - and the DH126 has a 9 pin connector at the decoder end so swapping out is easy and requires no rewiring. The TCS T1A comes with no harness, it will just plug in in place of the DH126. Or if the OP wants to stick to Digitrax, a DH155 will plug right in as well. It has extra functions, but also BEMF. I'm not particularly fond of Digitrax's BEMF, but it is tunable with a bunch of trial and error. TCS and ESU have automatic BEMF tuning.
To answer 'BigDaddy's' questions:
1. It appears to be random.
2. By feeder's I assume you're referring to the wire that send power to the track? If so, I only have one + and one - that are soldered to the track. The layout is fairly small.
3. I'm using a DCS-100 and DT400R, both Digitrax.
4. Can't answer this one. I was really into the hobby when I was younger, got out of it, and have gotten back in. I purchased the DCS100/DT400R off of ebay as part of a used pack. Before that I had one of the first Zephyr versions. When I was younger I do not remember the trains having this problem, but, I was only 10-15 at the time so I may not have been as nit picky with the detail back then.
I'll definetly check that cv you guys suggested. I recently purchased 2 new decoders, both DH166D's, one with sound and one without, so I'll see if those fix the problem once I get them installed. I prefer to stick with Digitrax decoders since they're all the same manufacturer and I don't have to read through a bunch of different brand manuals.